Botany and Zoology. 



439 



Gulf, and 625 from Panama, of which 218 are already known to be 

 common to the two — eighty-nine being common to the Gulf and South 

 America and twenty-three to the Gallapagos, which islands have very 

 little in common with South America, more with Panama, and some little 

 with the Indo-Pacific province. The Proboscidifera were found much 

 more local than the rest of the Gasteropods, and these than the Bivalves, 

 the spawn of which latter are borne through wide ranges by the currents. 

 The Fauna of Upper California, as shown by the collections of Mr. Nut- 

 tall and the United States Exploring Expedition, are quite distinct from 

 those of the Gulf; scarcely a score of species, and those in very limited 

 numbers, are found in common. Very little is accurately known of the 

 Fauna of the Peninsula. The shells on the Gulf side are, however, 

 mainly Panamic, on the Pacific side, Californian. Scarcely a single spe- 

 cies is common to West America and Polynesia, while not a few appear 

 identical with West Indian forms, especially in the Gulf. Several forms 

 reappear on the Gambia coast. A very few reach Britain, chiefly nest- 

 ling bivalves. The main object of the report was to reduce to a common 

 estimate all that was yet known on the subject, that future students 

 might not have to go over the same ground continually, and to point out 

 the causes of the present very unsatisfactory state of the science, as the 

 first step towards their removal. 



10. On the Vital Powers of the Spongiadce ; by Mr. Bowerbank, (Proc, 

 Brit. Assoc., August, 1856 ; Ath., No. 1505.) — The greater portion of these 

 observations were made on a new species of sponge, of a deep orange 

 color, that abounds on the rocks in the vicinity of Tenby between high 

 and low water marks, and which he has named Hymeniacidon caruncula. 

 He found that while in a state of repose oscula could rarely be seen in 

 the open state, but immediately after being placed in fresh sea-water these 

 organs were very shortly fully expanded, and streams of water were 

 ejected from them with considerable force ; this action continued for a 

 longer or shorter period at the will of the animal, and its termination 

 was sometimes abrupt and at other times very gradual. After the action 

 had ceased for a short period it might again be readily stimulated to a 

 renewal by a supply of fresh cold sea-water, and especially if poured on 

 to the sponge with some degree of force. The action of the oscula were 

 not simultaneous in all parts of the same specimen, and it frequently oc- 

 curred that while one group were vigorously in action another group were 

 in complete repose. The aspect of the oscula also varied considerably, — • 

 sometimes the membranous margins were projected in the form of short 

 tubes, while at other times they were contracted laterally so as to form a 

 tense horizontal membrane, with a widely-expanded central orifice. The 

 author also found the reparative powers of this species remarkably active. 

 If the sponge was cut into three pieces, and these were again brought in 

 contact, in less than twelve hours they became firmly re-united, — and 

 specimens of the same species placed in close contact were united to each 

 other in a few hours, becoming one sponge. The author, in conclusion, 

 briefly referred to the nutritive apparatus of the Spongiadse. He stated 

 that nearly the whole of the interior of the animal is one large stomachal 

 cavity, furnished abundantly with membranes covered with a coat of sar- 

 code, similar in every respect to the mucous lining of the intestines of 



