Mr. H. D. S. Gooclsir on new species of Crustaceans. 325 



XXXVI. — On several new species of Crustaceans allied to Saplii- 

 rina. By Harry D. S. Goodsir, M.W.S., late Conservator 

 of the Museum of the Roy. Coll. Surg. Edinburgh, Assist. 

 Surgeon in H.M. Arctic Exploring Ship Erebus. 



One of the most striking features in the structure of this pecu- 

 har form of Crustacean is the double eye in a single dark spot. 



The antennae are similar in form to those of the Isopoda, being 

 either filiform or almost truncate, the general form of these or- 

 gans in the Isopoda, and by no means like those of the Monoculi, 

 which are setaceous and very often dilated in the middle. As in 

 the Isopoda, they are short, being generally about as long as one- 

 half of the breadth of the body. 



The animals here referred to have a projection from the me- 

 sial line of the carapace, analogous to the rostrum, generally 

 found in the Monoculiy and in the extremity of this rostrum the 

 eye is generally situated. 



The first segment of the body is in all cases longer than the 

 remaining segments combined, and in some instances the lateral 

 edge is curved inwards and downwards, so as to give it the ap- 

 pearance and form of a carapace. The remaining segments of 

 the body are small, gradually decreasing from the second to the 

 terminal. 



In several species the terminal abdominal segment is provided 

 with a jointed pedicle on each side, which is armed at the extre- 

 mity with spines, and in some species this structure is exactly 

 similar to Monoculus. The anterior extremities are very short, 

 so much so as not to be seen extending beyond the edge of the 

 body ; generally however one or more joints of the last pair of 

 legs are seen posteriorly. 



The most striking character in this order of animals is the 

 double extremities, a character common to the Stomapoda and 

 Monoculi as well as this form of Crustaceans. As in Stomapoda 

 the two terminal filaments arise from one common pedicle, the 

 external one being much longer than the internal ; the former 

 also is chelate and three- jointed, the latter four-jointed. The 

 number of joints however in these legs varies. The legs arising 

 from the carapace (first thoracic legs) are not double, or if so, one 

 of the terminal filaments is obsolete. 



These animals are very active in their habits, and swim about 

 in company with the other forms of the family Pontia. 



Body depressed as in the Isopoda ; posterior thoracic legs 

 double. 



Sterope ovalis. Plate XL fig. 11. 



Rostrum not prominent; antennae unarmed, three- or four- 



