INVERTEBKATA, CRYPTOaAMIA, MICROSCOPY, ETC. 707 



MoUuscoida. 



New Genus of Polyzoa.* — The Eev. J. E. Tenison- Woods de- 

 scribes Euldimcnaria dncalis (evKTi/jicvos, well-built) as a very interest- 

 ing and curious genus dredged at a depth of 10 or 20 fathoms on 

 coral mud oft' Darnley Island. Itdifi"ers so comi)lutely from any of 

 the described families of the Cheilostomata that its afiinities and 

 relations must remain problematical until others are discovered. The 

 nearest family is the Selenariadte which have the polyzoary more or 

 less orbicular, convex on one side. Its singular beauty both as regards 

 design and ornament renders it a remarkable addition to an order 

 where beauty and variety are the rule. 



The genus is characterized thus : — Polyzoary free, upper surface 

 convex covered with cells, lower surface divided into five portions, 

 each containing large pores ; in the centre of the base a vermiculate 

 quiuque-partite body. 



The species is convex with pentagonal outline ; the edge circum- 

 scribed by a raised margin of five arches, whence it descends to a 

 broad pentagonal pedicel by five arched concave surfaces, which are 

 horizontally divided in the centre by a straight raised double ridge, 

 above and below the centre of which there is a large conspicuous 

 pore ; the pore above is semicircular, that below is perfectly round ; 

 both seem deep. The margin of each of the arched spaces curves 

 round into a loop at each side below the lower pore, and is curved 

 again in a contrary direction at each side so as to form another small 

 loop in which there is another small pore. Beneath the lower of the 

 two large central pores there are one or two conspicuous grooves to 

 the base. Ui^per convex surface covered with concave cells, with a 

 distinct raised margin ; mouth in the centre, semicircular, with a 

 raised margin. Shape of cells from oval to circular, a few almost 

 pentagonal ; the centre of the convex surface seems covered with cells 

 but they are worn almost smooth on both the specimens. The base 

 is vermiculate, but with a radiate tendency, and forming a quinque- 

 j)artite pattern. Between the margin of the five sides there are 

 ujiper and lower angular spaces, giving great elegance to the design. 



Dimensions : alt. 6, diam. of summit 8, of base 4^, lat. of five lateral 

 spaces 4J, alt. 3^ mm. 



The author is unable to suggest any explanation of the pores on 

 the sides or the organs which form the margins, transverse bands, &c. 

 It is quite evident that there must be some individuality in these 

 zoothomes apart from what we call the animal which dwells in the 

 cells, or the symmetrical arrangements of the species could not be 

 explained. 



Embryology of Tendra zostericola. f — In continuation of his 

 researches into the history of this form Herr Eepiachofi" now gives 

 some few details as to the stages subsequent to the blastula ; in which 

 there is to be observed a slight thickening of the ectoderm, on the 

 ventral surface ; this becomes gradually more marked and is evidently 



* 'Proc. Linn. Soc, N.S.W.,' iii. (1S78) p. 126. 

 t ' Zool. AnzL'iger,' ii. (1S79) p. 67. 



