418 



CRUSTACEOLOGY. 



Ar.'.-:!r.'ii- 

 des. 



Genus LIV. SalTiCUS. E}'es forming a horse-shoe 

 or parabole open behind. 



Family X. Tarantulides. 



Palpi very spiny, resembling arms ; mandibules ter- 

 minated by a simple hook ; the two anterior feet very 

 long, and antennseform ; the tarsi with an immense 

 number of joints. 



Genus LV. Tarantula. Palpi long, simply termi- 

 nated by a joint in the form of a hook ; body short and 

 depressed ; thorax reniform or lunated ; tail none. 



Genus LVI. Thelvphronus. Palpi short and thick, 

 terminated by a finger and thumb ; body oblong and 

 cylindrical ; thorax oval ; tail long. 



Family XI. Scorpionides. 



Palpi arm-shaped, terminated by a hand armed with 

 a forceps ; mandibules with a pair of forceps ; all the 

 feet alike in form. 



Genus LVII. Scorpio. Eyes six or eight; tail 

 jointed ; two laminated pectens at the base of the belly. 

 Genus LVIII. Chelifer. Eyes two or four; tail 

 none ; pectens none. 



Genus LIX. Cellularia. 



Observation. Besides the genera above denned, we 

 may add one more, viz. Cellularia, a most singular 

 animal discovered by the celebrated zoologist Montagu, 

 inhabiting the cellular membrane of the gannet, (Peli- 

 canus Bassanus, Linn.) which is not referable (as far as 

 we can judge from his description) to any of the fami- 

 lies hitherto established by Latreille. It appears to be 

 intermediate between Acaridcs and Ricinides ; we shall, 

 however, quote his description, as given in the first vo- 

 lume of the Wernerian Society's Memoirs, page 1 9 1 . 



" Ovate oblong, smooth, glossy white, with eight 

 short legs, furnished with several joints, and termina- 

 ted by bristles, two on each side approximating, and 

 near to the anterior end ; the others similarly disposed, 

 about one-third of its length from the posterior end : 

 of the posterior legs, the hindermost pair is furnished 

 with a very long bristle, the other pair usually with 

 two ; the anterior legs possess several bristles each. No 

 other appendages were discernible under the best con- 

 structed microscope, not even the mouth or eyes could 

 be clearly ascertained ; but beneath, «t the anterior 

 end, from whence the fore legs arise, there are four 

 light depressions, surrounded by dark lines, in the two 

 hindermost of which is a dark spot, but these had not 

 the appearance of eyes ; behind this part is usually a 

 fold in the skin, at which place there is an independant 

 motion : the feet are also observed to be in continual 

 alternate motion, whilst under the microscope. 

 " Size of Acarus Sim, or cheese mite. 

 " As far as I have hitherto observed, this insect is 

 peculiar to the gannet, and does not appear to inhabit 

 any other part than the cellular membrane : in some 

 subjects it is found in prodigious abundance, together 

 with the ova ; and no instance has occurred in which 

 it has not appeared more or less in every specimen dis- 

 sected. 



" To class this animal with any of the Linnaean gene- 

 ra is impossible ; nor am I acquainted with any genus, 

 in the arrangement of any of the more modern syste- 

 matic writers, in which it could with propriety be pla- 



ced. It appears to be more nearly allied to Acarus 

 than any other ; but the want of eyes, proboscis or 

 sucker, and palpi, will admit of no connection ; the 

 situation, too, of the legs seems to be characteristic. 

 Under these circumstances, I propose giving it a dis- 

 tinct place in the system of nature, under the title of 

 Cellularia Bassani, with the following generic cha- 

 racters : Head, thorax, and abdomen united ; no eyes, 

 antennae, palpi, nor proboscis ; legs eight, the four pos- 

 terior remote from the four anterior ; feet unarmed, but 

 furnished with bristles." 



From the above ingenious account, which is accom- 

 panied with figures, it is evident that it should form a 

 distinct family, which might with propriety be name;' 

 Ccllidarides, and be placed, as we have before mention- 

 ed, between the Miles and Tiques. 



Arachni- 



ORDER I. PODOSOMA .* 



Genera ;me 

 Specie?. 



1. Ntm- 



FHON. 



Grossipes. 



Family I. Nymphonides. 



Genus I. Nymphon. Fabr. Lamar. Latr. Pycno- 

 gonum. Oth. Fabr. Mall. Phalangium. Linn. Mont. 



Mandibular armed with a forceps. 



Sp. 1 . Grossipes. Body smooth ; feet very long. 



Phalangium grossipes. Linne. 



Nymphon grossipes. Fabr. Latr. 



Pycnogonum grossipes. Otho Fabricius, Miiller. 



Inhabits the Norwegian and British seas ; is not un- 

 common on most of our rocky coasts, being often 

 dredged up by the fishermen, who know it by the name 

 of sea spider. Fabricius says it perforates the shells of 

 mussels, (mytilli,) and sucks out the softer parts of the 

 animal. 



Sp. 2. Aculeatum. Body smooth ; feet very long Aculeatum. 

 and hairy about the joints. 



Phalangium aculeatum. Montagu. " 



Nymphon hirtum. Fabr. ? 



Phalangium hid urn. Turton. ? 



Inhabits the British sea. 



Colour, when alive, dusky black ; length about four 

 lines. 



This species was first noticed by George Montagu, 

 Esq. on the south coast of Devonshire. This is not ' 

 the Phalangium spinipes of Otho Fabricius and Gmelin, 

 as has been supposed by Montagu, that species being 

 referable to the following genus. 



Family II. Phoxichilonides. 



Genus II. Pkoxichilus. Lair. Pycnogonum. 2. Phoxi- 

 Otho Fabr. Phalangium. Montagu, Gmcl. emi.es. 



Mandibulce simple, without a forceps. 



Sp. 1. Spinipes. Feet very long and spinous. Spinipes. 



Pkoxichilus spinipes. Latreille. 



Otho Fabricius. 

 Gmelin. 

 Montagu. 

 Inhabits the Norwegian and British seas. 

 This species, which is certainly Phalangium spinosurn 

 of Montagu, when alive is of a rufous-brown colour, 

 and about a quarter of an inch in length. Two speci- 

 mens, which were most obligingly communicated by R. 

 Stevenson, Esq. from the Bell-rock light-house, on 



Pycnogonum spinipes. 

 Phalangium spinipes. 

 Phalangium spinosurn. 



* All the animals of this order are marine, and for the most part inhabit deep water or rocky shores : they frequently occur also 

 in pools left by the receding tide. The females of the first tribe are furnished with long jointed ovifera, which Latreille has impro- 

 perly named spurious feet, the use of which are to carry about their eggs. The same parts are said to be found in the second tribe 

 in Pycnogonum Balanomm ; but we have never been fortunate enough to detect them in any specimens we have hitherto examined. 

 Sec Linn. Trans, vol. is. p. 101. where this is noticed by our celebrated zoologist Montagu. 



