1G2 Mr. W. E. Collinge on 



EXPLANATION OF PLATE VIII. 



Fig. 1. Lateral view of the rhinarium of Hemigalus derby anus. 



Fig. 2. Anterior view of the same. 



Fig. 3. Superior view of the same. 



Fig. 4. Base of the left ear. s., supratragus or plica principalis ; b., bursa, 

 the margin of the posterior flap dotted in behind the edge of 

 the pinna; pi. aud;x>., internal aud external posterior ridges; 

 e., crest on outer side of pe. ; o., inferior orifice of meatus ; 

 ae. and ai., external aud internal anterior ridges, the former 

 bearing the tragus below, the latter the semicircular flap above. 



Fig. 5. Anal and genital area of male, a., anus ; sc, scrotum ; gl, gland ; 

 p., prepuce. 



Fig. 6. Left fore foot from below. 



Fig. 7. Left hind foot from below. 



XXII. — Some Observations o?i the Isopod Idotea hectica 

 (Pallas). By WALTER E. COLLINGE, M.Sc, F.L.S., 

 F.E.S., Research Fellow of the University of St. Andrews, 

 the Gatty Marine Laboratory, St. Andrews. 



[Plate IX.] 



In connection with an investigation which I am at present 

 carrying out on the British species of Isopoda of the Family 

 Idoteidae, Professor M'Intosh has very kindly placed at 

 my disposal a number of specimens, amongst which is one 

 from the Atlantic Ocean which I believe to be referable to 

 the Oniscus hecticus of Pallas. 



This species was described by Pallas in 1771 * from 

 specimens obtained from the Atlantic, though most of the 

 subsequent records are from the Mediterranean region. 

 Mievs f mentions having examined specimens from S. Europe 

 (P. B. Webb) - and Tripoli (T. Ritchie) in the British 

 Museum collection, and from the Museum d'Histoire naturelle 

 of Paris specimens from the Mediterranean (Roaa') } Nice 

 (Risso), Algeria (Lucas), and Bourbon (Breon). 



The /. viridissima of Risso is regarded as synonymous 

 with this species by Miers, who also places the Stenosoma 

 eruginosa of Costa in the same category, but with a query. 



So far as I am aware, 1. heclica has been only imperfectly 

 described and still more imperfectly figured ; the purpose of 

 the present communication is to supplement these. 



* Spicil. Zool. 1772, i. (fasc. 9) p. 61, pi. iv. tig. 10. 

 f Journ. Linn. Soc, Zool. 1883, A'ol. xvi. 



