Mr. Lubbock on new species of Entumostraca. 409 



turn. Styli caudales abdomine brcviores. Setae caudales stylia 

 loiigiorcs. 



This species belongs to a small group of the genus which con- 

 tains four others also. From C crassiusculus it may be at once 

 distinguisht'd by the two-jointed abdomen; from C. luticeps by 

 the caudal lamella being more than half as long as the abdomen 

 (excluding, of course, the lamella itself) ; and from C. vitreus, 

 agilis, and orientalis by the finger of the second antenna being 

 considerably longer than the second segment. 



The ccphalothorax, seen from above, much resembles that of 

 CoryciCiis styVferus, mihi. 



Specimens of this species wci"e often found in coitu, and when 

 so, clung together very tenaciously, not being in some cases 

 separated when put into spirits of wine, so that they were not 

 divided even by death. Prof. Dana was unable to discover any 

 sexual differences in the genus, but I always found in this spe- 

 cies the first segment of the abdomen of the male occupied by a 

 bright mass, which was absent from that of the female. The 

 vermiform mass of pigment attached to the eye, also, went con- 

 siderably further back in the male than in the female ; so that 

 I should be inclined to regard Prof. Dana^s representation of 

 C vitreus as that of a male, and that of C. agilis as that of a 

 female. 



Being the first species found in the British seas, I have named 

 it C. anglicus. 



Length of ccphalothorax '029, of abdomen -014; total •01. 



PI. XL figs. 14 to 16. 



MONSTRILLA. 



The genus J/o.^s/rzY/a and the family Monstrillidse v,-ere founded 

 by Prof. Dana for a single specimen caught by him in the Sooloo 

 Sea ; and I have now the pleasure to record a second species 

 found by me at Weymouth. Both appear to be very rare ; at 

 least Prof. Dana in all his travels met with only one specimen ; 

 and though I searched with great diligence_, 1 was scarcely more 

 fortunate. 



Monstrilla anglica. 



Frons quadrata, angulis rotundatis. Cepbalothoracis segmentum 

 primum postice paulo latiu?. Antennae 5-articulatpe, setis antenna 

 brevioribus. Abdomen 4-articulatum, segmentis subDequalibus. 

 Styli caudales oblougi, divaricati, setis 6 subsequis, diffusis. 



This species differs considerably from M. viridis. In the first 

 place the ccphalothorax is rather broadest behind instead of in 

 the middle, and the three posterior segments are somewhat 

 moniliform, so that their sides do not form an even line. The 



