734 SUMMARY OF CURRENT RESEARCHES RELATING TO 



ment of which is carefully described. There are a pair of muscles 

 arising just behind the cephalic region, which are of especial im- 

 portance in the action of the heart. In a fresh living form the cardiac 

 pulsations may be seen to be extraordinarily rapid, and when they 

 become slower, the valve of the muscles is very clearly seen. The 

 general structure of the heart of Cetochilus is repeated in other 

 Calanidae, but in CalaneUa there is an aorta of exti-aordinary length ; 

 the heart of Lhthyophorba and Temora is greatly widened in its 

 posterior half. The heart appears to be defended by two tactile setae, 

 which arise from the sides of the second thoracic segment, and which 

 may be seen to be provided with nerves given oif from a ganglionic 

 cell. In addition to these, there are in the succeeding segments 

 paired tactile setfe, which are larger in the male than in the female. 



In dealing with the unicellular tegumentary glands, the author 

 states that he is able to confirm the account of Professor Haeckel 

 with regard to Sapphirina and Sapphirinella, which was of great 

 interest, as from it we first learnt of the innervation of these glands. 

 As a rule a single, more or less pyriform, glandular cell is found 

 at the hinder end of the furca, and this opens to the exterior by 

 a large pore. In some forms this pore is surrounded by a chitinous 

 ring. The gland generally contains clear vesicles which run together 

 and pass out from the pore as a drop. In Temora there is a second 

 glandular cell, placed in the last abdominal segment ; a nucleus to 

 the cell can rarely be observed. The f ureal glands are developed in 

 the metanauplius stage. A large number of flask-shaped glands are 

 frequently developed in the cephalothorax and in the thoracic seg- 

 ments ; if we take as an example Temora we find them to be pyriform 

 and to have more or less highly refractive contents, with a large and 

 distinct pore. These glands, which may also be developed on the 

 appendages, seem to aid in the preservation of the species. 



Others, which are found on the genital segment of the female, 

 appear to have a difierent function, for they would seem to furnish a 

 secretion by which the spermatophore of the male is attached to the 

 body of the female. They are largely developed on the two anterior 

 abdominal segments of IchtJiyopJiorba denticornis, where they call to 

 mind the clitellum of the Oligochteta, although, of course, they are 

 not completely continued over the whole of the dorsal surface. 



In the second, or systematic, portion of his paper, Professor Claus 

 describes a new genus, Eucalanus (for Calanus mastigoplwrus), and 

 gives an account of some species already known to science, together 

 with some remarks on genera insujficiently characterized. 



Development of Cetochilus.* — Dr. C. Grobben has selected C. 

 septentrionalis for the study of Copepod-development. Numerous 

 studies have already been made of the frse-living forms, and Glaus' 

 well-known work deals exhaustively with the external form and with 

 the characters of the appendages. The egg of the form selected 

 offers peculiar advantages for the study of the earlier stages, as it is 

 transparent, is of some size, and each egg is laid separately. 



* Claus' Arbeiten, iii. (1881) pp. 243-82 (4 pis.). 



