Miscellaneous. 279 



the surface of the ovum, and when the dark masses and the dissepi- 

 ments have attained a sufficient concentration. The central rosettes, 

 or large rosettes of Ludwig, are purely imaginary phenomena, 

 assumed (rather than observed) in accordance with an illegitimate 

 analogy between the phenomena witnessed at the surface of the 

 ovum and those which are supposed to take place in its depths. 



To sum up, the protoplasm, in the Araneida, moves from the 

 centre towards the periphery, where it makes its appearance in the 

 form of disks or cones of ejection, surrounded by the spheres of the 

 rosette, which may be compared to cones of elevation. There is 

 eruption through a chimney, which subdivides towards the centre of 

 the ovum. By this means the ovum is transformed into a mero- 

 blastic ovum with multiple cicatriculse. This is the end of the first 

 phase. 



During the second phase the regular meroblastic segmentation of 

 the cicatriculae takes place. The nuclei divide, and with them the 

 dark stellate forms, and the rosettes of Ludwig. In this way is 

 produced a second generation of stars and rosettes. As this goes on 

 the granules and the protoplasm of the gcrmiuative areas are at- 

 tracted by the dark disks, which finally absorb them entirely. In 

 the third generation the brilliant rosettes cease to be visible, which 

 is due to the disappearance of the thick dissepiments of protoplasm 

 and their absorption into the dark disks. 



The protoplasm of the surface continues segmenting, and finally 

 forms a single layer of flattened polygonal cells. This is the blasto- 

 derm, which covers the whole surface of the ovum. 



In none of the species that I have studied have I found the central 

 cavity or blastoccele, any more than the. radial orientation of the 

 vitelline masses, such as are described and figured by Ludwig. 



From these observations it results that the ovum of the Spider 

 presents an intermediate type between the ova with general super- 

 ficial segmentation of the Crustacea, such as Peneus, and the ova 

 with regular discoidal segmentation, such as those of certain fishes ; 

 that is to say, it has a blastulation intermediate between periblastu- 

 lation and discoblastulation. It greatly approaches the ova of 

 Chelifer (MetschnikofF), Tetranychus (Claparede), and of insects (Bo- 

 bretzky). Thus is plainly manifested from the outset the affinity of 

 the Araneida with other groups of Arachnida and with the insects. 



My observations have been made upon the ova of Pholcus opili- 

 onicles, Epeira diadema, Epeira fasciata, Agelenalahyrinthica, Latro- 

 dectus malmignatha, and some small undetermined species. — Comptes 

 Bendiis, January 24, 1881, p. 200. 



Aeineta dibdalteria, a new Sjpecies of Marine Infusorian from the 

 Gulf of Genoa. By Dr. Conead Parona. 



When seeking Protista at Sestri Levante (Riviera di Geneva) and 

 in the sea- water that I had brought home with me for subsequent 

 study, I foimd last September a new Acinetine, which struck me by 

 its very peculiar characters, and especially by the suckers, which are 

 not borne by a trunk and are not ramified. 



