698 SUMMARY OF CURRENT RESEARCHES RELATING TO 



mucli variation in the conduct of the larvae ; some exhibit indications of a 

 normal development, but the majority undergo a gradual process of de- 

 generation, accompanied by considerable increase in size; the proboscis 

 cavity becomes smaller, its wall thinner, and its muscles fewer ; the noto- 

 chord, collar cavities, and gill-pouches disappear; the ectoderm becomes 

 much thinner, and the greater part of the nervous system disappears. This 

 larva was observed at Bemini, Bahamas. A little later, a much larger 

 larva, found at Nassau, New Providence, was found to undergo still further 

 degradation, the ectoderm over the greater part of the body becoming a 

 mere flattened epithelium, the trunk cavity a minute solid rod, and the 

 proboscis cavity much further reduced than in the Bemini larva. 



The cause of this degradation is probably the compulsory shifting of 

 the larvae into deep water ; if this be admitted it follows that, in some cases 

 at least, the transmission by a larva of hereditary changes is only possible 

 on the application of certain stimuli, that where these are wanting, some 

 larvae are highly variable, that the variations due to change in environment 

 may be uniform and definite, and that the changes may result in the 

 hypertrophy of the larval organs. 



Trichodina paradoxa.* — Prof. H. Ludwig has a note on the remarkable 

 parasite of the Firolidae, lately described by M. Barrois,t showing that it 

 is nothing more than the separate capitulum of a gemmaeform pedicellaria, 

 and almost certainly of SpliserecMnus granulans. 



Echinodermata. 



Mergui OpMurids.| — Prof. P. Martin Duncan has a report on the 

 thirteen species of Ophiurids collected by Dr. J. Anderson in the Mergui 

 Archipelago ; of these nine are new and one is the representative of a new 

 genus — OpMocampsis, which is placed near OpMothrix ; this form is able 

 to bend its arm in a vertical downward plane and has no upper arm-plates. 

 In a succeeding contribution,§ the author deals with some points in the 

 anatomy of Opliiothrix variabilis, and OpMocampsis pellicula; as to the 

 latter, the opposed surfaces of the arm-bones are remarkable, particularly 

 because of the enormous upper muscle-area on the aboral surface of the 

 arm-bones, and the " peg " is absent ; there are no knobs on the adoral 

 surface, while the large size of the slot and the obliquity of the apophysis 

 allowed of great downward bending as well as of lateral movement. 

 Especial attention is given to the arrangement of muscles in Ophiothrix, 

 and it is clear that the development and distribution of muscles is not the 

 same among all Ophiuridae. With regard to the subsequent term " chewing 

 apparatus," the author points out that the arrangement of the jaws does not 

 admit of chewing, though the process of filtering occurs. 



Coelenterata. 



Chromatology of Anthea cereus.]] — Dr. C. A. MacMunn has found 

 chlorophyll as well as chlorofucin in extracts of the " yellow cells." If 

 sections of the tentacles are made after hardening in alcohol the mass of 

 yellow cells are found packed in the tentacle at random as it were, and it 

 seemed to be quite clear that these bodies are not secreting cells. The 

 chlorophyll of Anthea differs from other chlorophylls in its remarkable 

 instability towards caustic alkalies, and the chlorofucin which accompanies 



* Zool. Anzeig., x. (1887) pp. 296-8. f See this Journal, ante, p. 373. 



% Joum. Linn. Soc. Lond., xxi. (1887) pp. 85-106. § Ibid., pp. 107-20 (4 pis.). 



II Quart. Joum. Micr. Sci., xxvii. (1887) pp. 573-90. 



