DR. T. DAVIDSON OX EECENT BRACHIOPODA. 229 



habitat is peculiar. Mr. Dall places it with two ? ? in his genus Glottidia ; but we have 

 no direct evidence that it belongs to that genus ; and in a letter to me, dated 29th Jan., 

 1885, that writer says, "we have recently received Glottidia ptjramidata from the 

 Florida Keys, where it grows larger, and with a slightly more thickened shell, than 

 the more northern specimens, hut is otherwise identical ; and there can be no doubt 

 that it is identical with the Lhigula {Olottidia) originally described from Cuba, which 

 long antedates Stimpson's name." It will, however, be better, until the matter is finallv 

 determined, to leave it among the uncertain species and under its present name. 



130. Glottidia (?) semen, Broderip, sp. (Plate XXVIII. fig. 12.) 



Lingula semen, Broderip, Trans. Zool. Soc. vol. i. p. 141,, pi. xxiii. fig. 17, 1835; G. B. Sowerby, 

 Thes. Conch, p. 338^ pi. Ixvii. fig. 11, 1846; A. d'Orbigny, Voyage dans I'Amerique Meridionale, vol. v. 

 p. 071, 181.7 ; Davidson, Ann. & Mag. Nat. Hist. 2ud ser. vol. ix., May 18.12; L. Reeve, Conch. Icon., 



almost perfect accord with what we have found with regard to the genital glands in the Ecardine Brachiopod Lhv- 

 ffida." He notes the exception that the genital hands contained within the mantle-sinuses are attached to the outer 

 leaflet of the mantle instead of the inner, " and have no genital artery, as is the case in Waldhei mia " (p. 25-5). 

 It was only after considerable hesitation that Dr. Beyer was forced by the weight of evidence " to believe in the 



fact that, so far, at least, as Linr/iila is concerned, the sexes are united within the same individual Hancock's 



views arc still correct," he states, " so far as the genital ridges within the mantle-sinuses are concerned. "Within 

 these, according to our interpretation, both ova and spermatozoa develop side by side : it is, however, different within 

 the perivisceral chamber. Here the ova are confined principally to the mesenteric bands and their reflected portions 

 — in other words, occupy a more central position with relation to the animal — while the spermatophorcs occupy the 

 peripheral walls of the visceral chamber, in fact, are almost exclusively developed from the peritoneal epithelium 

 (covering in many layers, and much modified) the lateral body-wall, and to a slight extent also the dorsal and 

 ventral. 



"While, then, in our opinion, Litujula is an hermaphrodite animal, it is nevertheless rare to find both ova and 

 spermatozoa present in equal proportions, and equally developed in the same individual. In those individuals in 

 which, for instance, the male elements largely preponderate fully developed ova are sometimes very few, and may 

 even be entirely confined to the mantle-sinuses, so that on a superficial examination they might be entirely over- 

 looked. A more careful examination of an entire series of sections, however, will invariably result in finding both 

 male and female organs of generation within the same individual. 



" As already mentioned, the principal seat of development of the spermatophorcs is the lateral body-wall. This 

 arrangement seems to be in perfect harmony with the close apposition in some individuals of the cup-shaped internal 



extremity of the segmental organs to the lateral body-walls, which, so far, has remained unexplained We 



would therefore consider them as movable organs intended to take up spermatozoa or ova, and carry them into the 

 mantle-chamber at certain intervals ; and in accordance with this double function the relative position of their internal 

 openings changes ; at one time, it will bo found snugly apphed to the lateral body-walls, and then spermatophorcs 

 may be seen within the oviducts ; at another, their ciliated inner extremity will point directly backward towards the 

 most posterior portion of the visceral chamber, into which fully developed ova usuidly drop, and under these circum- 

 stances ova may be detected within the oviducts. Having never seen either ova or spermatophores within the same 

 oviduct, it is not to be supposed that fructification takes place inside the animal, but rather that this occurs in the 

 mantle-chamber or in the sea- water. . . . AVe think that there can now hardly bo any doubt as to the ova springing 

 directly from the cells composing the peritoneal lining membrane. . . . The development of the spermatophores also 

 takes place from peritoneal epitheUum." See PL XXX. figs. 12, 1:3, 14 of this Monograph, where some of 

 Dr. Beyer's illustrations are reproduced. — A. C] 



