46 DB. M'INTOSH on BRITISH SALPiE. 



showing two in apposition, is stiff atnd artificial — a state in whicTi it 

 would never have been represented if he had seen living specimens. 



The individuals adhere to each other by a considerable extent 

 of their edges, including the attenuated extremities, and form a 

 sort of interrupted double row by being alternately attached. 

 Thus, for instance, the second is attached to the first on its rigJit 

 side, the point of its attenuated process reaching beyond the vis- 

 ceral speck. The third adheres to the left side of the second, its 

 point also proceeding beyond the nucleus. The long axis of each 

 is nearly parallel to that of the entire chain. Dr. McCulloch 

 states that " each individual adheres to the preceding by a regular 

 sequence of superposition lengthwise, so that the whole form a 

 long simple chain." He must have viewed the riband laterally. 



Sometimes two individuals of large size (each 3 inches long) 

 swam together — the fragment of a chain ; and numerous single 

 ones of the aggregate as well as of the solitary form occurred. 

 The proper sphere of this species seemed to be from a point some 

 feet below the surface, downwards, since any met with at the sur- 

 face were mutilated, dying, or dead. One individual of the ag- 

 gregate form was caught, just beyond the rocks, with a young spe- 

 cimen (true embryo of Professor Huxley) in its interior (fig. 1). 

 The embryo, a, adheres to the nucleus, l, of the parent by the pos- 

 terior extremity, and thus its anterior orifice agrees with that of 

 the adult — a situation affording every facility for the passage of 

 constantly renewed currents of water through its cavity. The 

 adult specimen in this case exhibits a very common anastomosis 

 of the muscular bands. In life these bands are scarcely seen, 

 except as slight wrinkles during contraction ; it is the immer- 

 sion into strong spirit that renders them so visible. 



The youngest condition of the solitary form observed is pro- 

 bably represented by that in the interior of fig. 1; the next, in 

 the free form shown in fig. 4, where the preponderance of the 

 visceral over the locomotive apparatus is very apparent. This is 

 exactly the reverse of what takes place in the Ascidians, whose 

 young forms acquire the maximum locomotive, the adult the max- 

 imum visceral. Each has its various requirements amply supplied 

 in the structures developed at the time. The rounded opake 

 body a, fig. 4, would seem to be embryonic, since it diminishes 

 progressively as the size of the animal increases, and in the adult 

 disappears. In fig. 2 a developing chain is observed at /! A 

 peculiar network of vessels occurs over a limited space in two of 

 the solitary forms figured (h, iigs. 2 and 3). 



