1888.] MICROSCOPICAL JOURNAL. 1-^7 



J. C. Draper : — Medical Physics, p. 508. 



M. N. Miller :~ Practical Microscopy, p. 36. 



yonnial of the Royal Microscopical Society, 1SS2, p. 147. 



Popular Science Monthly^ vol. vii, p. 177. 



The various encyclopaedias. 



REPORTS OF RECENT ARTICLES. 



Structure of Lamellibranch Muscle.* — Dr. R. Blanchard has studied 

 the histology of muscle fibres in the lamellibranchs and illustrates with nu- 

 merous wood-cuts: — I. Observations, which confirm those of Banois and 

 Tourneux of muscle fibres striated obliquely from the adductor muscles. 3. 

 In Mytlhis maxi?}ius from the adductor muscle spindle-shaped cells with 

 longitudinal striation and an ovoid granular nucleus bordered at each end by 

 a very distinct tapering granular cone, which is lost in the longitudinal striaj. 

 The nucleus lies on the border of the cell. 3. In Ostrea ediiiis^\-AX. de can- 

 calc in adductor m.uscle cells similar to those in 3, but much longer, some cells 

 measuring 2 mm. 4. In Ostrea ediiUs^ var. de Marennes the adductor muscle 

 contains some elongate cells with very peculiar oblique striation in various 

 patterns. Some are with two oblique stria; crossing each other, while others 

 have oblique lines which run toward each other and meet and stop in the 

 centre of the cell. The nucleus here is also marginal and the cell fusiform. 

 5. In Gryphcea angulata cells from the adductor muscle have the surface 

 marked with oblique striae of various direction, producing zig-zag or undulat- 

 ing lines. Forms from other animals are also described, but they are not 

 very unlike some of those already mentioned. 



Remarks on Hydra. — Prof. Leidy remarked, at the Academy of Natural 

 Science in Philadelphia, that in our fresh waters there occur two well-marked 

 species of hydra, the one of a bright green color, the other pale brownish or 

 reddish. These, judging from the descriptions and figures, appear to him to 

 be the same as the European species H. viridis and H. fiisca. The late 

 Prof. L. Agassiz regarded them as difierent and named them //. gracilis and 

 H. carnea. Familiar as he was with both the European and American ani- 

 mals, his opinion might be considered conclusive, but the onlv distinctive 

 character he assigns to each seems not to be correct. Of our green hydra he 

 observes that, unlike the European, it has the power of extending its body in 

 a remarkable degree. Opposed to this view, Rosel, in i75'^., represents H. 

 viridis in the same condition and with the arms in the same proportionately 

 short state. In other characters, the speaker found our green Hydra to accord 

 with H. viridis ; and, further, in respect to the sexual organs. Prof. Allen 

 Thompson describes the latter as producing a single ovary near the middle of 

 the body and two or three spermaries from the body just below the arms. 

 The same condition he had observed in ouf green hydra. As regards our 

 brown hydra, Agassiz gives, as the distinctive chai^acter, that it has very short 

 arms, while the European has long ones. Ordinarily, this appears to be the 

 case, but on several occasions the speaker had observed our brown hydra, 

 after it had been kept some time in an aquarium where there was compara- 

 tively little food, elongate its arms, extremely attenuated, even to a length of 

 three inches. 



He had the opportunity of seeing both the green and brown hydra west of 

 the Rocky mountains, and these he found to accord in character with our 



* Bulletin de la Societe Zool, de France, 1888, p. 75. 



