439 



PROTOCOCCUS. 



PROTOPTERUS. 



470 



Proteus angttinus. 



animals, the largest blood-globules : first, because the size of the 

 latter in the naked Amphibia in general is the largest in the animal 

 kingdom ; secondly, because, remarkable as it is, the blood-globules 

 are here (in the naked Amphibia) so much the larger, the longer the 

 gills continue in the larval state ; hence the land and water salamanders 

 have much larger blood-globules than the frog. I conjectured also 

 that the Protei (probably also the Siren, &c.), because they permanently 

 have both gills and lungs being therefore permanently larvas would 

 be found to have the largest blood-globules. The latter are indeed 

 gigantic ; flat, oval, resembling those of the salamander, and from 

 l-30th to l-40th of a Paris line in length; hence, as minute points, 

 visible to the naked eye. They are from once to twice the size of the 

 blood-globules of the salamander, nearly three times as large as those 

 of the frog, and about twelve or fifteen times the size of those of man. 

 In a female I found the ova very beautifully developed ; their struc- 

 ture, as well as that of the ovary, corresponding perfectly with that of 

 the other naked Amphibia, especially the Triton. The smallest ova 

 consist of a delicate chorion, yellow yolk, large germinal vesicle, and a 

 manifold germinal spot. I regret to Bay that in the otherwise tolerably 

 developed testes of the male there were no spermatozoa. I conjecture 

 however that the spermatozoa of this animal resemble those of the 

 Triton. I would just remark, that the form and size of the blood- 

 globules, the formation of the ova, and the form of the spermatozoa, 

 in different animals, have a great zoological and physiological interest. 

 Already is it in my power from a drop of blood or semen placed 

 before me, to determine with the microscope, not only the class, but 

 frequently the genus and the species from which these fluids have 

 been taken." 



Sir Humphrey Davy, in his ' Consolations in Travel," gives a very 

 graphic account of finding these subterranean animals in Illyria. 



[SlBE.V.] 



PROTOCOCCUS, a genus of PlanU belonging to the natural order 

 Confervacece. It is made the type of a tribe Portococcidce, belonging to 

 the sub-order Palmdlacecr. 'f \\e\Palmdlacece are plants of the simplest 

 kind, consisting of single cells somewhat globose or elliptical, and 

 either free or connected together by a slimy mucus or frond. The 

 latter forms constitute the tribe Coccochlorida, whilst the former are the 

 Protococcida. In this tribe are included the genera Protococctu, 

 Jfcematococcta, C'hlorococcum, Pleurococcia, Hormotpora, and Stereo- 

 cocctu. Of these genera Protococcut is the most interesting, as affording 

 the red cell*, which, frequently occurring on snow, have got for it the 

 name of the Red-Snow Plant. The genus is thus denned : Plant 

 consisting of aggregated naked globules filled with minute granules, 

 nd sessile on a gelatinous transparent mass. [Snow, RED.] 



PROTOMEDEA. [ACALEPH*.] 



PROTONOPSIS. [AMPHIBIA.] 



PROTO'PTERIS, a genus of Fossil Plants, from the coal formation, 

 i ncluding Sigillaria punctata of Brongniart. (PresL) 



PROTO'PTERUS. Under this name Professor Owen, in the manu- 

 script catalogue of the Museum of the College of Surgeons, in June, 

 1337, recorded the principal characters of an extraordinary animal 

 which he supposed to belong to the Malacopterygious Fishes. In the 

 same year, Dr. Natterer published an account of a nearly allied animal 

 under the name Lepidotiren paradoxa. This account appeared in the 

 nnnals of the Museum of Vienna, and is drawn up from two specimens 

 discovered by the author of the paper in South America. The memoir 

 of Dr. Natterer on the South American Lepidosiren was followed by 

 one from Professor Owen, in the ' Linuj'an Transactions ' (vol. zviii. 

 part 2, p. 327), in which that anatomist describes in detail both the 

 external characters and internal anatomy of the Protopterui above 

 mentioned ; and as he found this animal must be referred to the same 

 genus as that discovered by Dr. Natterer, he adopted his generic 

 term, and applied the name of Lepidosiren annectent to the species. 

 The last-mentioned animal, says Professor Owen, " was presented to 

 the lioyal College of Surgeons, June, 1837, by Thomas C. B. Weir, Esq., 

 together with a smaller dried specimen inclosed in indurated clay 

 baked hard by the sun. Several species of insects peculiar to the 

 Gambia, or African form*, accompanied these specimens. It is a 

 female, with the ovaria well developed, and measures twelve inches 

 eight lines in length ; its greatest circumference is four inches and a 

 half. The head commences by an obtuse muzzle, and gradually 

 enlarges in all its dimensions to the gill-openings, which are situated 

 immediately anterior to the base of the pectoral extremities: the 

 length of the head, from the snout to the gill-opening, in one inch 



eleven lines. The anus, or rather the cloacal vent, is a small elliptica 



aperture marked with radiating lines, which is situated three lines 



behind the ventral filaments, and offers the same peculiarity as doea 



i that of the Lepidosiren paradoxa in not being situated on the median 



! plane ; in the present specimen it was on the right side of a longi- 



j tudinal fold of integument which occupied the middle line. The 



| distance from the vent to the end of the tail is five inches. The trunk 



gives a wide elliptical transverse section, and maintains a pretty 



i uniform size, slightly decreasing in breadth to the ventral filaments. 



Beyond these the tail becomes more rapidly compressed, and after a 



short distance diminishes also in vertical dimension, till it ends in a 



thin point. A membranous dorsal fin commences at the distance of 



four inches from the snout, and, gradually increasing to the height of 



five lines, is thus continued into the caudal membranous expansion. 



Lepidosiren annectens. 



This fin is supported by numerous soft, elastic, transparent rays, arti- 

 culated to the extremities of the superior and inferior peripheral 

 spines of the caudal vertebras; the under part of the caudal fin 

 commences about one inch behind the vent. The entire body ia 

 covered with cycloid scales, which are relatively larger, but have the 

 same general structure and disposition as in the Lepidosiren paradoxa. 

 They present a subcircular form, with a diameter of about three 

 lines ; their posterior margin adheres to the strong cuticle with which 

 they are removed, as in other fishes; the anterior lies freely in a 

 corresponding groove of the chorion. The disposition of the mucous 

 pores and ducts upon the head is very similar in the two species of 

 the Lepidotiren, judging from the figure given by Dr. Natterer. A 

 linear series of mucous pores encircles each eye, and from the posterior 

 angle of this series the lateral line commences. This line extends 

 backwards nearly parallel with the dorsal line, situated a little more 

 than one-fourth of the vertical diameter of the body of that lino, 

 until it nearly reaches the ventral extremities, where it bends dowu 

 to midway between the dorsal and ventral margins, and so continues 

 to the end of the tail. The rudimentary filamentary fins, the analogues 

 of the four ordinary extremities in the Vertebrata, permanently 

 represent in the present singular animal the earliest embryonic condi- 

 tion of the pectoral and pelvic members. They are round, filiform, 

 gradually attenuated to an undivided point, resembling tentacles or 

 feelers rather than fins or legs, and doubtless restricted to their tactile 

 functions. Each filiform member is supported by a single-jointed, 

 soft, cartilaginous ray. The pectoral tentacles are somewhat shorter 

 and more slender than the ventral ones ; the former are two inches, 

 the latter two inches four lines in length. The branchial apertures 

 are narrow vertical slits four lines in extent. The eyes appear exter- 

 nally as two small round flat spots of a lighter colour than the 

 surrounding integument ; they are situated seven lines from the end 

 of the snout, and nearly the same distance apart from one another. 

 Each of these simple visual organs measures one line and a half in 

 diameter ; it is not defended by any palpebral folds of the skin ; the 

 cornea is thin, sufficiently transparent to allow the lens to be visible 

 even in the specimen preserved in spirits. The nostrils are situated 

 at the under part of the upper lip, within the opening of the mouth. 

 They appear as two small perforations leading to blind sacs. About a 

 line behind the lower lip, between it and the teeth, there project six 

 soft papillose processes, of a triangular form. Behind the upper lip 

 there arc eight similar papillose processes, four on each side. There 

 are two small, slender, conical, sharp-pointed and slightly recurved 

 teeth, which project downwards from the intermaxillary bone, to which 

 they are attached by ligaments. These teeth, in their paucity, relative 

 size, and mode of fixation to the maxillie, resemble those of the 

 Chinuera and some of the extinct cartilaginous fishes, as Cochliodui 

 and Ceradodui ; but they are unlike these in their microscopic struc- 

 ture, and differ from any known dental apparatus in the class of fishes, 

 in the modifications of the working surface which at once adapt them 

 for piercing, cutting, and crushing. The strength of the jaws, and 



