471 



PROTOROSAURU3. 



PSELAPHUS. 



471 



the ibt ot the muscle* which work them, an proportionate to the 

 be and formidable character of the maxillary denUl plates. There 

 are no lingual, palatine, pUrygoid. vomerine, or pharyngeal teeth." 



The skeleton of this eoriooa fish U partly cartilaginous and partly 

 bony, and the OMWOUS portions are of a green colour, as In the Common 

 Uar-Fiah (/Mow rulgaru). [BELOXK.] 



lo writ-win j the principal character* of the ikeleton of the Lepi- 

 dosiren. " we obtain, say* Professor Owen, " good evidence of it* 

 iehthyie nature. If indeed the specie* had been known only by it* 

 skeleton, no one could hare hesitated in referring it to the class of 

 Fuhea; but in that class it would hare offered a most singular and 

 interesting combination of the cartilaginous and osseous types. 



"The central element* of the vertebral column, the basis of the 

 skeleton, exhibit a persistence of its primitive embryonic condition, 

 nch as has hitherto been witnessed only in the sturgeon and cyclos- 

 tomatoo* Gshrs; but the superior arches and spioous appendages, 

 instead of retiming the cartilaginous state, are converted into the 

 tough elastic fibrous texture characteristic of the skeleton of fishes. 

 The cranium in like manner present* an extremely novel combination 

 of the cartilaginous and bony states, both as regards its partial ossifi- 

 cation and the condition of the ossified part*. 



" It is only in the higher cartilaginous fishes, for example, that the 

 maxillarr, palatine, and pterygoid bones are blended together to form 

 the simple superior dcntigerous arch, or upper jaw. The composition 

 of tne lower jaw corresponds with that which characterises most of 

 UM oweous fishes, and U more simple than in the Amphibia. The 

 confluence of the cranial vertebrae reminds one of the condition of 

 the skull in the siren ; but no vestige of a preoperoular bone is present 

 in any of the Perennibranchiate*. The spheuoideum basilare, aa it 

 exist* in the sturgeon, is here seen in its fully ossified state. As the 

 basis of the vertebral column present* a condition analogous to that 

 which characterises the early embryonic periods of the higher Verte- 

 iro/o, so also the extremities retain their simple\tructure aa when 

 they first bud forth, and are devoid of any trace of digital divisions : 

 still the march of development has begun, and we perceive by the 

 numerous joint* of the cartilaginous ray that its direction is towards 

 the iehthyie modification of the great vertebral plan." 



This animal is regarded by aotne naturalists as one of the Amphibia. 

 In many point* of it* structure it certainly does approach that group of 

 auimaU, especially in the condition of its air-bladder or lungs and its 

 branchue ; but as regards the former, we find considerable advances 

 are made toward* the reptilian structure by some other fishes ; and it 

 may be remarked that the present animal still differs widely from the 

 Amplibia in possessing distinct large scales. There is another cha- 

 racter which it appears is of the highest importance in determining 

 the cla-s to which the Lepidosiren belongs, namely, the structure of 

 the nostrils. " In the organ of smell," says Professor Owen, " we 

 hare at last a character which is absolute in reference to the dis- 

 tinction of fishes from reptiles. In every fish it is a short sac com- 

 municating only with the external surface ; in every reptile it is a 

 canal with both an external and an internal opening. According to 

 this teat, the Lepidosiren is a fish ; by its nose it is known not to be a 

 reptile. In other words, it may be said that the Lepidosiren is proved 

 to be a fish, not by it* gills, not by it* air-bladders, not by its spiral 

 intestine, not by it* unossified skeleton, not by its generative appa- 

 ratus, nor it* extremities, nor its skin, nor its eyes, nor its ears but 

 simply by it* nose; so thst at the close of our analysis we arrive at 

 this very unexpected result, that a reptile is not characterised by its 

 langs nor a fish by it* gills, but that the only unexceptionable 

 distinction U afford- d by the organ of smell." 



In conclusion, the author state* "From every group of fishes 

 however the Lepidusiren is sufficiently distinct to form a type, not 

 merely of a genus, but of a family; and in the natural system it 

 forms a link connecting the higher Cartilaginous Fishes with the 

 Sauroid genera Pvlyptenu and Ltpidotteut ; and at the some time 

 make* the nearest approach iu the class of Fishes to the Perenni- 

 branchiate Reptiles." 



The South American Lepidosiren (Lepidotiren paradoxa) greatly 

 resemble* the specie* above described, but differs somewhat in its 

 proportion*. The whole length of L. paradoxa includes eleven 

 length* of the head, measured from the end of the mouth to the gill- 

 openings; in the L. anaetteni the total length of the animal includes 

 little more than six lengths of the bead. This specie* U therefore 

 <U*Uoguuhed from the L. paradora by the shorter relative length of 

 the trunk as compared with the head. 

 PROTOKOSAU'RUS, Meyer's name for the Fossil Monitor of 



'i ..:..-. i 



PROTOZOA, a term applied by Oken to the lowest forms of animal 

 life. /VfpAyla nas been applied to the same forms of vegetable life. 

 A* employed at the present day, it embraces the group of hftaoria 

 termed by Kbreoberg PolyaaHrua [IvrtnoKu], the Wiiopwla of 

 l>ujrdin embracing the Poraminifera [FoRAMlBlfERA] snd the 

 Sponge*. pramiAM.1 The Anita of M'Leay, and the Oozoo of 

 Catua, correspond to this section of the animal kingdom. 



rii'.v ((T.KVM..I..] 



PRUNELLA, a grnus of Plants belonging to the natural order 

 Labiattt. It ban two inferior Unr-m ; the filament* bifid, one branch 

 Uurcn; the anther* all 2 celled; the corolla ringent, the upper lip 



concave, entire; the calyx ultimately closed and compressed, the 

 upper Up flat, truncate, 3-toothed, the lower lip bifid. 



/'. rulgraii. Self-Heal, is a native of Europe and Asia ; very plentiful 

 n America and Auitralia, and also in England. The leaves are 

 t ilked, ovate or oblong, toothed or deeply pinnatifid ; the upper lip 

 of the calyx with short truncate mucroiiate teeth ; the lower lip with 

 ovate-lanceolate muoronate teeth, the two longest stamens with a 

 straight apinous root at their apex. The flowers are purple, white, or 

 nearly red. In the British specimens the leaves are nearly entire. 

 This plant is considered astringent, and was formerly used in fluxes 

 and gargarisms for apthm and inflammation of the fauces. Its repute 

 is now merely in name. 



P. grandijlora has petiolate ovate leaves, quite entire or toothed, 

 the lateral teeth of the upper lip of the corolla lanceolate; the corollas 

 large, more than twice as long as the calyx. It it native throughout 

 Europe in woods and shady places. The flowers are of a purple or 

 violet colour, seldom white. 



(Uabington, Manual of Britith Botany.) 



PRUNUS, a genus of Arborescent Rosaceous Plant*, belongs 

 to the Amygdaleous division of the order, and comprehends 

 several of our domestic fruits. The Cherry, Bird-Cherry, Plum, 

 Damson, Sloe, Bullace, and Apricot, are all comprehended in the 

 genus as limited by Linmcus ; but in the opinion of some modern 

 botanists, the true Plums require to be separated from the others, and 

 should exclusively constitute the genus Pruniu, while the others ore 

 to be considered as belonging to two other genera, represented by the 

 Cherry and the Apricot. In this view of the subject, each genus is 

 characterised thus : 



Armtniaca, the Apricot. Drupe woolly outside. Stone blunt at 

 one end, sharp-pointed at the other, with a furrow passing all round 

 it, and an even surface. Young leaves rolled up. 



Ceratia, the Cherry. Drupe smooth, without bloom. Stones 

 roundish, smooth. Young leaves folded flat 



Pruniu, the Plum. Drupe smooth, covered with bloom. Stouo 

 sharp-pointed at each end, furrowed all round, and smooth on the 

 surface. Young leaves rolled up. 



Of the Plum genus, thus restricted, there is in common use the 

 Garden Plum (P. Jomestica), with all its numerous varieties, the 

 Bullace (P. inxititia), and the Sloe (P. tpinota). These plants arc 

 distinguished specifically by botanists, but apparently without reason. 

 It is the opinion of the best experimental physiologists, that the Sloe 

 of our hedges was the origin of the others ; and certainly there is not 

 more difference between a Sloe and a Greengage than there is between 

 a German Quetsche and an English White Magnum- Bouum. Several 

 other species belong to the genus, but they are of no moment, with 

 the exception of a plant called Pruniu Coccomilia, which inhabits the 

 mountains of Calabria, and has a great reputation in Italy on account 

 of the tonic qualities of its bark. 



PSALIODUS. [GoAT-SccKB8.] 



PSALI'ODUS, a genus of Fossil Fishes. [Fisn.] 



PSAMMA, a genus of Grasses belonging to the tribe A rundin&e, 

 It is known by its flower being enveloped in long silky hairs, the lower 

 glume shorter than the upper, and its panicle being spike-like. 



P. arenaria, Sea-Reed, Marram, is the only British species. It U 

 found on sandy sea-shores, where its roots assist in binding the 

 shifting sands. 



PSAMSIO'COLA, M. De Blainville's name for a genus of Conchifers 

 (Psammabia and Piamiiwttea, Lam.) belonging to Lamarck's family 

 Nymphacca. 



'PSASIMO'DROMUS, a genus of Saurian Reptiles. 



PSAMMODUS, a genus of Fossil Fishes. (Agassiz.) [Fisn.] 



PSAMMOSAURUS. [MONITORIDJD.] 



PSARia [MusciCAMD*.] 



PSK'LAPHUS (Herbal), a genus of Coleopterous Insects, but now 

 regarded as a family, to which the name Pselaphida is applied. The 

 Ptelaplti are very minute insects, and most remarkable in their struc- 

 ture. By some entomologists they are arranged with the Brachclytra, 

 owing to their having the wing-cases short and truncated ; and by 

 others they are placed in the section Trimcra, their tarsi having but 

 three joint* : in the classification of Latreille they constitute the 

 last family of Coleopterous Insect*, being placed at the end of the 

 Trimera. 



Scarcely any of the known Pidaphi exceed one-twelfth of an inch 

 in length, and the greater portion of them are under that size : they 

 prey upon other insects still smaller than themselves, and are found 

 under stones, and amongst herbage, especially iu damp situations. 

 Some species are found under the bark of trees, and in putrid wood, 

 and the species of one of the genera are found in ants' nests (the 

 genus Ctavigtr). They are often collected during the winter mouths 

 by shaking the moss from the root* of tree*, or from old walla, over a 

 piece of white paper or cloth. They are probably found iu all parts of 

 the world. The principal characters of the group are as follows : 



Head moderately large, exserted, and most commonly of a trian- 

 gular form, being broad at the base and attenuated in front ; the eyes 

 moderately prominent, sometimes wanting; palpi usually large und 

 generally 4 -join ted ; antenna: usually 11 -jointed, sometimes with 6 

 joints, and in one genus apparently having but one large joint, 

 generally equal to about half the length of the insect, and increasing 



