Dr. J. E. Gray on a new species of Sphserium. 465 



EXPLANATION OF PLATES XIIL XIV. & XV. 



[The numbers attached to the details of figures i. iii. and v. indicate the 

 same parts throughout.] 



Plate XIII. 

 Fig. I. Diastylis Rathkii. 



2. Carapace seen from above ; showing the manner in which the 



lateral angles, a, a, meet, without uniting, in front of the an- 

 tennal segments, b. 



3. Carapace seen from beneath, with the gnathopoda in position. 



4. a. Upper antenna, attached to the carapace, seen from below. 



5. Lower antenna; a. olfactory organ. 



6. Mandible. 



7 & 8. Maxillffi. 



10. Maxilliped; a. branchial sac. 



11 & 12. 1st and 2nd gnathopoda (2nd and 3rd maxillipeds). 



13 & 14. Two anterior pairs of thoracic legs. 



15, 16 & 17. The three posterior pairs; a. hairs. 



18. Appendages of the two anterior pairs of abdominal segments 

 in the male. 



19. Caudal segments and appendages. 



20. Section of shell. 



21. Gizzard-like structure of stomach. 



Plate XIV. 

 Fig. II. Cuma scorpioides. 

 Fig. III. Eudora truncatula. 

 Fig. IV. Cuma Edwardsii. 

 Fig. V. Halia trispinosa. 



Plate XV. 



Fig. V. Halia trispinosa continued. 



Fig. VI. Bodotria arenosa (after Goodsir). 



Fig. VII. Venilia gracilis. 



Fig. VIII. Larva of Hippolyte varians. 



1. Eyes. 



2. Upper antenna. 



3. Lower antenna. 



4. Pair of larval feet (the first maxilliped of adult). 



5. One of the two next pair. 



XLII. — Desct'iption of a new species of Sphserium found near 

 London. By Dr. J. E. Gray, F.R.S., P.B.S. &c. 



These shells were first brought to me at the British Museum 

 by an intelligent collector, Mr. John Rowse of Brownlow Street, 

 Endell Street. He discovered them on the 17th of May, in the 

 Grand Junction Canal near Kensal Green, and the following day 

 most kindly furnished me with several living specimens for 

 examination. They are not abundant in the locality named. 



They are decidedly distinct from any of our British specimens, 

 but bear a very great resemblance to Cyclas rhomhoidea of Say, 

 found in the rivers of North America. 



Ann. ^ Mag. N. Hist, Ser. 2. Vol xvii. 30 



