the Genus Diphya off Ireland. 165 



DiPHYA ELONGATA. 



Spec. Char. Both portions of similar form and nearly equal 

 size ; the swimming cavity of each likewise similar, and, 

 as well as the nutritive organ, extending the whole length 

 of the body. 



The aniinal or animals when first taken were united, as 

 shown in the sketch, the whole body being of a most beau- 

 tiful transparency ; so much so, that it was extremely difficult 

 to distinguish it in the clear sea-water. The only coloured 

 part was the long tentacular appendage, which was of a light 

 reddish colour, and only to be seen in the larger individual. 

 The motion of the Diphya through the water m as caused by 

 the contraction of an elongated cavity having an open round 

 aperture fringed with what had the appearance of a soft mem- 

 brane without any ciliee, by which contraction the animal was 

 rapidly propelled through the water with the pointed end 

 foremost in a series of jerks, agreeing with the motion attri- 

 buted to the genus by Eschscholtz. At other times, when lying 

 undisturbed, there was no appearance of animation except a 

 very slight movement of the tentacula, nor was the circula- 

 tion pei'ceptible under a strong lens ; but on examination 

 under a powerful microscope, a circulation was discovered 

 commencing in the canal which originates at the base of the 

 tentacular appendage, and continuing throughout the nutritive 

 organ. 



In removing the Diphya for examination in the microscope 

 the two bodies separated, when each appeared quite a distinct 

 animal, capable of precisely similar motions ; the only differ- 

 ence between them being, that the smaller one was destitute 

 of the tentacular appendage, and the pointed end was fur- 

 nished with a lamina, as in sketch. 



Of the nature of the connexion between the two indivi- 

 duals, or of the functions of the tentacular appendage, I was 

 unable to satisfy myself during the short period allowed me 

 for their examination ; the smaller one having died the day 

 after its separation, and the larger one having remained in a 

 languid state, w ith its tentacula contracted, until the third day 

 after its capture, before which time I had not the means of 

 examining it under a good microscope. 



I have delayed this communication so long in the hope of 

 being able to procure further specimens, but as yet I have 

 been unsuccessful ; although the probability is, that the ani- 

 mal may not unfrequently be met with on this coast, as Mr. 

 Thompson lately pointed out to me a dried specimen of an- 

 other individual of the same species, which I had picked up 



