206 Mr. Lubbock on two nev) Subgenera of Calanidse. 



the middle of the dorsal surface of the first abdominal joint. It 

 is hollow and empty with soft elastic sides^ and y^jth of an inch 



In all the specimens I have seen, this organ has formed a right 

 angle with the longer axis of the body, as I have drawn it ; but 

 this position would be such an obstacle to rapid motion, that I 

 consider it owing only to spasmodic contraction of the animal 

 when put in spirits of wine. It would probably during Ufe be 

 extended in the axis of the body, as in Caligidce, and would 

 partly supply the place of the abdomen, and act as a rudder. 



This organ might be considered either as the external ovary, 

 or as a spermatic tube similar to that which Siebold has described 

 in Diaptomus Castor*. In support of the latter hypothesis it 

 may be adduced, that the organ in question differs from all other 

 known external ovaries belonging to this family, in being attached 

 to the back instead of the under surface of the body, and in 

 being long and cyhndrical instead of pear-shaped. In shape it 

 agrees exactly with Siebold's drawing of the spermatic tube in 

 Diaptomus, and at its base is a quantity of hard, reddish, irre- 

 gular matter, which forms a small lump on the left side, and is 

 firmly attached to the body of the animal. This strongly reminds 

 one of the glutinous substance by means of which the spermatic 

 tube is attached to Diaptomus, and which is driven out by the 

 expulsive matter. If we consider it as a true external ovary, how 

 can we account for this deposit ? 



It is also worthy of notice, that in Templeton^s paper on 

 Anomalocera there is figured (fig. 22) and described a " biarti- 

 culate spatulate appendage, which is confined to the left side of 

 the female, and attached to the first joint beneath ; it is probably 

 a collapsed ovary." 



Might not this be a spermatic tube ? In Gaimard's ' Voyage 

 en Scandinavie,' a female Calanus hyperboreus is represented 

 with an appendage, evidently a spermatophore, attached below 

 to the penultimate thoracic joint. It is true that this organ is 

 ringed, and difi"ers very considerably both from Siebold's figures 

 of the spermatic tube in Diaptomus, — from the above-mentioned 

 doubtful appendage of ^woma^ocera, — and from that of the present 

 species ; still it establishes the fact, that this mode of fecundation 

 is very generally pursued in this curious family. In all these 

 cases, however, it is attached below. 



On the other hand, we may observe, that its position, though 

 curious, is not entirely anomalous, for Notodelphys Ascidicola, 



* Annales des Sciences Naturelles, 2ik1 series, torn. xiv. ; and Baird's 

 British Entomostraca, p. 223. 



