NOTES AND EXHIBITS. 425 



to their hiding place. These larvae did not seem to have any idea 

 of direction, for they frequently attempted to go quite away from 

 their hiding place, but were prevented by the ants blocking their 

 further passage in that direction. 



Mr. D. G. Stead exhibited a mature intra-uterine foetus of the 

 Little Saw-Shark Pristiophorus cirratus (Latham), and, for com- 

 parison, the head of a half-grown example of the same species; 

 and he pointed out that an examination of the rostral lamina or 

 "saw,' in the mature foetus of Pristiophorus cirratus, revealed 

 the highly interesting fact that it was armed on each side, at 

 regular intervals, with long spines only; there being none of the 

 small intermediate spines which are so characteristic of the 

 " saw " in the adult or in the half-grown specimen exhibited, In 

 the possession of this character, the foetus suggested the large 

 predaceous Saw-fishes of the genus Pristis. It was interesting 

 to note also that these teeth were not fixed rigidly at right 

 angles to the " saw " as in the adult, but were movable, directed 

 backward, and lay pressed close against each side, thus protect- 

 ing both foetus and parent during parturition. Another fact 

 that was worthy of mention was that the subrostral tentacles 

 were about twice as long in the foetus exhibited as they are in 

 the mature fish. 



Mr. Stead also exhibited the right chela of a large Mangrove 

 Crab, Scylla serrata (Forskal), the dactylus of which was very 

 curiously malformed. In addition to being considerably dwarfed, 

 there was a large vertical outgrowth from its upper border, 

 resembling closely an open " nipper," even the teeth being 

 pi'esent. 



With reference to the fibre exhibited by Mr. R. T. Baker at 

 the May meeting and commented upon by Mr. A. Gr. Hamilton 

 at the June meeting, Mr. Maiden expressed the opinion that it 

 was probably the product of a marine plant, Posidonia australis 

 Hook.f.(Naiadea3). "The bases of the stems covered with the 

 filamentous remains of old leaf-sheaths " is a character of the 

 genus, those of P. australis being covered with longer and finer 

 29 



