404 



CRUSTACEOLOGY. 



Crustacea. 

 i.meari». 



Miasma. 



Penantis. 



Acanthi- 



Sera. 



61. Pa- 

 so pp. 



Ceii. 



BBS. 



Talpa. 



Sp. 1. Linearis. Head with one little tubercle. 

 Hand of the second pair of feet with three teeth on the 

 inner edge. 



Cancer linearis of Linne; Aslacus atomos of Pennant; 

 Caprella linearis of Latreille ; Ouiseus scolopendrioides 

 of Pallas. 



Inhabits the European Ocean, affixing itself to fuci 

 and other marine plants. Colour, when alive, brown, 

 inclining to cinereous, beautifully spotted with rust- 

 colour. 



Sp. 2. Phasma. The first joint of the body with 

 two spines ; a third spine on the anterior part of the 

 second joint ; a fourth spine on the head, all pointing 

 forward. Hands of the second pair of feet with one 

 strong spine. Colour generally pale olive green. Dis- 

 covered on the coast of South Devon on fuci, by Mr 

 Montagu, and described in vol. vii. of Linnean Transac- 

 tions, by him. 



Sp. 3. Penantis. Back without spines ; anterior 

 part of the head produced into a spine ; hands of the 

 second pair of feet with one tooth. 



Astacus atomos of Pennant. 



Common on the Devonshire coast. 



Sp. 4. Acanthifera. Back, especially the hinder part, 

 spiny ; inner edge of the second hands lunate-exca- 

 vated. 



Caprella acanthifera, Leach's MSS. 



Discovered in Devonshire, where it is not uncommon. 



Genus LXI. Panope. Body depressed. Eyes si- 

 tuated on the vertex of the head. Antennae four joint- 

 ed; the upper pair, with the basilar joint, largest; the 

 second and third equal, but rather shorter than the first; 

 apical joint very small ; inferior pair also composed of 

 four joints, shorter than the first joint of the upper pair. 

 Feet compressed and armed with strong nails ; the an- 

 terior pair situated on the base of the head, the wrist 

 jointed. Hands of the second pair armed with teeth 

 on their inner edge. Fins of a leathery-membranaeeous 

 substance, cylindrical and elongated. Anus produced, 

 having a few obscure small tubercles on each side and 

 under. _ 



The pouch of the female with four valves. 



Sp. 1. Ceii. Base of the fins with a process resem- 

 bling the figure 6 ; the hands of the second pair of feet 

 with two obtuse teeth on the thumb side of the hands. 

 Anus with three processes. 



Inhabits the European Ocean, attaching itself to 

 whales, and, according to Latreille, to fishes of the genus 

 Scomber. 



Oniscus ceti of Linne ; Pycnogonum ceii. of Fabricius. 

 Panope ceii, Leach's MSS. 



Family XVII. Apseudii. 



Genus LXII. Apseudes. Body six jointed, tail with 

 six segments, the last largest, armed at the apex with 

 appendices. Feet fourteen, the anterior pair with 

 a finger and thumb ; the second pair compressed and 

 dentated; the third and fourth alike and simple; the 

 fifth with a double nail ?; the sixth and seventh spurious. 

 The superior antennas with a biarticalated peduncle 

 armed at the apex with a jointed seta ; the inferior an- 

 tennae bifurcate. 



Sp. 1. Tulpa. Rostrum acute, with three excavated 

 longitudinal grooves. 



Cancer gammarus tulpa of Montagu ; Apseudes talpa, . 

 Leach's MSS. 



Inhabits the British Ocean ; length four lines; colour 

 yellowish- white ; is very rare. 



Mas. Montagu, Leach, 



ORDER III. MYRIAPODA. 



Family XVIII. Asellides. 



Crus'acea. 



I. The four antenna? very distinct. 



Genus LXII1. Asellus. Tail composed of one ex Asm- 

 piece, with two longitudinal foliaceous double-jointed lvs. 

 lamellae, and two bifid styles inserted about the middle 

 of the posterior margin. Antennas setaceous ; the last 

 segment composed of a great many smaller joints. 



Sp. 1. Vulgaris. Colour cinereous, often spotted with Vulgaris, 

 grey or white. 



Inhabits ditches and wells very frequent, and is con- 

 sidered as a proof of the goodness and purity of the 

 water. 



Oniscus aquaticus of Linne and Donovan; Idotca aqua- 

 ilea of Fabricius; Entomon hieroglyphicum of Klein; 

 Asellus vulgaris of Latreille. 



Genus LXIV. Idotea. Tail witli two or three seg- 6i. Iootfa. 

 ments, and two longitudinal plates as in the genus 

 Asellus. The internal or middle antennae composed of 

 four joints, and placed somewhat above the exterior ones. 



Genus Stenosoma of Leach. 



* Body linear, external antennae very long. 



Sp. 1. Hecticus. The segments of the abdomen la- jj t , | CH8i 

 terally dilated. Colour cinereous brown, or greenish- 

 brown, sometimes bordered with grey or cinereous brown. 



Inhabits the European Ocean. 



Oidsctis linearis of Pallas and Pennant ; Oniscus hec~ 

 ticus of Gmelin. Idotea tridentata of Latreille is only 

 a variety of this species. 



** Body thickest in the middle. Idotea, Leach. 



Sp. 2. Entomon. Body of an oblong oval; the seg- Entomon. 

 ments swelling at the sides ; tail conical and elongated, p TE 

 having a tooth on each side of the base. See Plate CCXXT 

 CCXXI. Fig. 7- Fig. 7.* 



Inhabits the European Ocean. 



Oniscus entomon of Linne and Pennant; Cymothoa 

 entomon of Fabricius; Oniscus oestrum, Donovan, in 

 Rees' Cyclopaedia, article Entomology, plate x. 



It is very probable that Oniscus marinus of Pennant 

 is merely a variety of this species ; both are found on 

 all our rocky coasts in the greatest plenty : it differs 

 merely in having the tail more conical than in entomon, 

 and having no teeth at the base; there are, however, so 

 many intermediate varieties, that it cannot with pro- 

 priety be considered as a distinct species. 



•S^. 3. CEstrum. Segments of the abdomen slightly cSstruii. 

 prominent at the sides. Tail deeply notched, with a 

 very small protuberance in the middle of the notch. 



Inhabits the European Ocean. 



Oniscus oestrum of Pennant. 



Genus LXV. Anthura. Body linear; tail with 65. As. 

 two broad moveable plates on each side, which, when thus*. 

 the animal is alive, much resemble a five-petaled flower. 

 Antennae short, the interior or upper pair rather longest. 

 Anterior pair of feet furnished with a moveable hook 

 or thumb. 



Sp. I. Gracilis. Lateral appendices of the tail ob- Gracilis, 

 liquely truncated. Colour pale, coloured with rufous. 



Inhabits the British seas, but is very rare. 



Oniscus gracilis, Montagu; Anthura gracilis, Leach's 

 MSS- 



Observation. Oniscus cylindricua of Montagu, Lin- 

 nean Transactions, vol. vii. p. 71- plate 6". fig. 8, seems 

 to belong to a genus nearly allied to Anthura ; but as 

 no specimen has ever occurred to us, we must content 

 ourselves with transcribing the description given by 

 that author. 



" Oniscus *ylindfkus, with a smooth, glossy, cylin- 



