1G2 Mr. W. E. Collinge on 



EXTLAXATIOX OF PLATE VIII. 



Fiff. 1. r>atei"al view of tbe rhinariuin of Hemigalus derby anus. 



Fifl. 2. Anterior view of the same. 



Fiy. 8. 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 ; ^>/. and ;)P., internal and external posterior ridges ; 

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

 ne. and ai., external and internal anterior ridges, the former 

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



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

 J)., prepuce. 



Fig. 6. Left fore foot from below. 



Fig. 7. Left hind foot from below. 



XXII. — Some Observations on the Isopod Idotea liect.ica 

 {Pallas). By WALTER E. COLLINCxE, M.S^., F.L.S., 

 F.E.S., Ile.search Fellow of the University of 8t. Andrews, 

 the Gatty Marine Laboratory, St. Andrews. 



[Plate IX.] 



In connection with an investigation wliicli I am at present 

 carrying out on the British species of Isopoda of the Family 

 Idoteiclse, Professor M'Intosh has very kindly placed at 

 my disposal a number of specimens, amongst which is one 

 Irom the Atlantic Ocean which I believe to be referable to 

 the Oiuscus 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. 

 Miers t mentions having examined specimens from IS. Europe 

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

 Museum collection, and from the Mu.seum d'Histoire naturelle 

 of Paris .specimens from the Mediterranean (it!oM.r), Nice 

 {Risho), Algeria [Lucas) ^ and Bourbon {Breon), 



Tlie /. viridissima of Risso is regarded as synonymous 

 with this species by Miers, who also places the Stenosoina 

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



iSo tar as I am aware, 1. heclica has been only imperfectly 

 described and still more imperfectl}' figured ; tiie purpose of 

 the present communication is to supplement these. 



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

 t Journ. Linn. Soc, Zool. 1883, vol. xvi. 



