Ch. IV.] CONTENTS OF THE TOWING NET. So 



anomalous forms, with the foot variously modified for swim- 

 ming. The Pterosoma was established as a genus by Lesson, 

 upon a species he found swimming in the vicinity of New 

 Guinea ; but either the drawings of his animal are very 

 badly executed in all the books, or the one found in my net 

 must be a second species, for there is but little resemblance 

 between them. Another delicate animal of the same class 

 was the Firola, a transparent creature, with a long proboscis, 

 and swimming by means of a well- developed fin in the lower 

 part of its body. A third was still more curious — an elon- 

 gated, transparent body, without eyes or tentacles, but 

 furnished with two pairs of fins and a fish-like tail, the whole 

 body like a minute arrow, and hence called Sagitta. It 

 darts through the water by sudden and instantaneous jerks, 

 during which it is lost to view for a moment. So trans- 

 parent is the body that the whole internal organisation may 

 easily be observed, and the circulation of granules, upwards 

 (towards the head), in the neighbourhood of the tail on either 

 side the body, and in the middle downwards towards the 

 tail. This animal is referred by Prof. Huxley to the 

 articulate division of animals. Another of these nucleo- 

 branchs, as they are termed, because their respiratory and 

 digestive organs form a kind of nucleus on the posterior 

 part of the back, was the pretty little curly-sheUed Atlanta 

 — shell and animal equally transparent, the latter with eyes 

 and tentacles, and moving actively by means of a fan-shaped 

 fin. AU these delicate oceanic animals have a remarkable 

 range, being found for the most part both ia the Atlantic 

 and Indian Oceans, as weU as in the Mediterranean Sea. 



Only once did I meet with the little purple Glaucus, an 

 oceanic nudibranch, of which so much has been written. 

 This sea-lizard, as it has been called, soft and fragile as it 



