654 



Crossurus RATHKE. (Not different perhaps from genus Tanais). 



Note. Add genus Rhcea EDW. (Ann. des Sc. Nat. xm. 1828, 

 pp. 292 296, PL 13 A), unless it be better to refer it to the 

 Ampliipoda. Genera Eupheus and Olisca Risso, seem to be un- 

 certain, and require confirmation by more diligent observation. 



Perhaps also will have to be placed here amongst the Isopoda, Oniscus 

 arenarlus SLABBER Natuurk. Verlust. Tab. xi. fig. 4, genus Pterygocerct 

 LATE., Cuv. R. Ani. 2nd eM. 1829, rv. p. 124. 



Family XX. Idoteidea. Tail mostly composed of only three 

 distinct segments, with last segment large, scutiform. Abdominal 

 feet branchial ; last pair of feet forming opercular lamina? covering 

 the branchias beneath. No appendages exsert in the last segment 

 or at the sides of tail. Antenna? four, very frequently unequal, the 

 middle approximate. Mandibles destitute of palps. 



Anthura LEACH. Four antennae, short, subulate. Body slen- 

 der, vermiform. Anterior feet incrassated, terminated by an in- 

 curved hook. Tail with two distinct segments. 



Sp. Anthura grant-is LEACH, Oniscus gracilis MONTAGU, DESMAR. Crust. PL 

 46, fig. 13, MILNE EDWARDS Hist. not. des Crust. PL 31, figs. 3 5. 



Idotea FABR. Middle antennas short, with four joints, the last 

 elongate, cylindrical; external antenna? large, with first five joints 

 thicker, the rest more slender, running into a terminal seta. All 

 the feet of trunk terminated by an incurved claw; those of the first, 

 second and third pairs raptorial, incrassated at the apex and turned 

 forwards. Branchial feet of tail covered by the last pair of feet 

 changed into two valves articulated by means of a hinge to the 

 last segment. 



Sp. Idotea entomon FABR., Oniscus entomon L. (in part), PALLAS Spicil. 

 Zool. ix. Tab. v. figs, i 6, DE GEER Mem. p. s. a I' Hist, des Ins. vi. PL 

 32, figs, i 10, KATHKE Beitr. zur Gesch. der Thierwelt, i. Danzig, 1820, 

 Tab. iv. This animal was found in the Baltic Sea ; it attains a length of 

 i "9"'. Its two small black eyes are situated at the side of the head in a 

 round pit, and are not, as is erroneously supposed, simple, but each of them 

 consists of a group of more than 50 small oval eyes placed close together. 

 Idotea Lichtensteinii KRAUSS, Sudafrik. Crustaceen, Stuttgart, 1843, Tab. 

 IV. fig. 4. 



Idotea linearis LATR., Stenosoma lineare LEACH, EASTER NatuurL Uitsp. 

 II. Tab. XHI. fig. 2, DESMAR. Crust. PL 46, fig. 12; from the Baltic, about 

 i" long. 



