ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 493- 



conditions it shelters in any convenient recess, among del)ris or in 

 leaf-axils. Hahrotroclia torquata sp. n. has similar many-toothed rami, 

 but the spurs are of quite ordinary form, whilst the habitat is usually 

 mosses growiu*;" in wet positions. The corona has a peculiar " smothered " 

 appearance, due largely to the unusual height of the lower lip and the 

 resulting course of the secondary wreath of cilia. H. spicula sp. n. is 

 a widely distributed but rather small form, noteworthy chiefly for the 

 solitary spine and its unusual position, viz. on the pre-anal segment. 

 When the animal is in its most retracted position, the spine projects dis- 

 tinctly at the hinder end of the body. H. ligula sp. n. is distinguished 

 mainly by a small fleshy ligule or tooth, standing erect at the dorsal 

 end of the nexus, between the two pedicels of the corona. Gallidina 

 hilfingeri sp. n. was first discovered by the late Forstmeister Bilfinger, of 

 Stutto'art, whose name has now been associated with it. It is notable 

 for a curious series of prominences upon the central and posterior trunk, 

 and for its very minute and widely separated spurs. 



Ech.inoderm.8 . 



Structure of Echinocardium Test.* — H. L. Hawkins describes a 

 new method for exposing sutures in dried specimens of Echinoids. The 

 method combines the processes of staining and etching, depends on the 

 presence of tissue between the plates, and gives a lasting result easily 

 photographed. The author describes for. the first time the complex 

 structure of the anterior ambulacrum, and indicates a corresponding 

 development in Heter aster oblong ii,s and ScMzaster. 



A general description is given of the growth of compound ambu- 

 lacrals among the great groups of Echinoids, and, as a result of the 

 facts brought forward, it is argued that " plate-crushing " is due solely 

 to the mechanical " growth-pressure " caused by the development of new 

 plates. The appearance of tuberculation corresponding in arrangement 

 with the ambuiacral elements is considered to be an after-effect of their 

 fundamental characters, and to modify very slightly, if at all, the struc- 

 ture of the areas. 



Coelentera. 



Structure of Pseudoplexaura crassa.f— W. M. Chester gives an 

 account of the minute structure of this Plexaurid. The branches show a 

 central horny axis, a thick coenenchyma, and an outer zone of polyps. 

 The horny axis shows a medullary portion composed of large chambers 

 arranged end to end, and a peripheral layer of smaller, less regularly 

 shaped ones arranged side by side, and irregularly overlapping one 

 another. The coenenchyma has, not far from the axis, a region of large 

 longitudinal canals. These are sometimes prolonged at their tips into 

 sole'nia. The polyps are long, and have ten to twelve pairs of pinnae on 

 each of their tentacles. When expanded they hide the coenenchyma. 

 Groups of small, crowded, irregularly stellate, purple spicules occupy the 



* Proc. Zool. Soc, 1913, pp. 169-81 (1 pi. and 3 figs.), 

 t Proc. Amer. Acad., xlviii. (1913) pp. 737-73 (4 pis.). 



