Dli. T. DAVIDSON ON RECENT BKACIIIOPODA. 73 



Fifi;s. 11-23. IVuhlheimia (or Macandrevia) craftiww, Miillcr, sp. \\-\^ b. A series of dift'ercut ages. 

 11. A very large example (after Sars). 15-15 b. A very minute or first stage (after Friele). 

 10. Tlic first stage of the development of the loops with a coherent apopliysis (Friele). 



17, 17a. Sijccimen a little further advanced: a, lamellae; b, vertical walls; c, tube (Friele). 



18, 18 ff. Opening of the posterior end of the tube (Friele). 19. Perforation of the lateral 

 walls (Friele). 20, 21. Connection with the septum is broken (Friele). 22. The lamel- 

 processes separated. 23. Adult and fully developed loop. All the specimens from Norwe- 

 gian waters. (See Friele, Develop. Skelet. in Jl^alr/heimia, Archiv Math, og Naturviden- 

 skab, ii. p. 380, pis. i. & ii., 1877.) 



Plate XIII. 



Fig. 1. IVuldhelmia {ov Macandrevin) cranium, Miiller, sp. Dorsal view of the animal, much enlarged 

 (after Hancock), o, pallial lobe ; Zi, body; c, peduncle; d, great inner pallial sinus; e, outer 

 ditto ; /, genitalia appearing through the walls of the sinuses ; y, marginal fold ; h, setae ; i, 

 cireumpallial vessel ; _;', extreme pallial mai-gin ; k, two lobes corresponding to cavities at the 

 sides of the foramen ; /, similar lobes corresponding to the cavities in the umbonal region of 

 dorsal valve ; m, ridge resulting from the union of the pallial margins ; n, extremity of anterior 

 occlusoi's ; 0, ditto of posterior ocelusors ; p, ditto of dorsal adjustors ; q, ditto of divaricators. 



Fig. 2. Ventral view of the same (after Hancock). The letters up to k as in fig. 1 : — I, extremities 

 of the occlusor muscles ; m, ditto of divai'icators ; ni*, portions of ditto, corresponding to 

 the accessory divaricators ; n, ditto of ventral adjustors ; o, ditto of peduncular muscle ; 

 p, peduncular nerves. 



P'igs. 3-9 ff. Terebratella coreanica, Adams and Reeve, sp. 3. Type specimen figured by Reeve. 4-4 c. A 

 fine and large specimen. 5, 5 a. A still larger example {Terebratula miniata, Gould), dredged 

 by L. V. Schrenk, from Hakodadi, Japan. G, Ga. An elongate globose variety, dredged by Capt. 

 St. John in Tsuga Strait. 7. Interior of dorsal valve, to show loop. 8, 8 b. Elongate variety 

 (7". 2?o(/c//a;-</«, Davidson) . 9, 9«. Var. Bo«cAo«/i, Davidson. Specimens 4, 5, fi, 7, and 8, in 

 the Davidson Collection, Geol. Dept., British Museum ; 9, in the Zool. Dcpt., British 

 Museum. 



SECOND SERIES. — ZOOLOGV. VOL. IV. ]() 



