162 HELIX-LABYRINTHUS. 



296. H. erecta MOUSSON, Mai. Blatter, 1873, p. 3. PFR. Novit. 

 Conch., iv, p. 116, 1. 127, f. 1-3 ; Monographia, vii, p. 461: DOHRN, 

 as syn. of subplanata 1. c. supra. H. labyrinthus var. sipunculata 

 FORBES, Proc. Zool. Soc. Lond., 1850, p. 53, t. 9, f. 4. H. annulifera 

 PFR. Proc. Zool. Soc. Lond., 1851, p. 260; Monographia Hel. Viv., 

 iii, p. 255. REEVE, f. 555. 



H. labyrinthus may be distinguished from H. plicata by the 

 greater development of the teeth ; the outer basal tooth is broad, 

 flat, plate-like, and approaches to within one millimeter of the parietal 

 lamina. The base is more swollen than in H. plicata, more broadly 

 constricted behind the peristome and the inner part of the aperture 

 is narrower. The size is very variable. 



Chemnitz is quoted as the authority only by courtesy ; his figure 

 is very poor, and his synonymy includes all the figures of the Laby- 

 rinthus group known to him. Deshayes first rectified the synonymy 

 of this species and H. plicata. Dohrn, who declares that he cannot 

 recognize H. labyrinthus Chemn. (" Was nun H. labyrinthus Chemn. 

 betrifft, so habe ich bereits erklart, das ich sie nicht kenne und 

 nicht kennen kaun," etc.), adopts the name subplanata of Petit. 

 That name was not published until six years after Deshayes had 

 redefined and figured plicata, and figured what he understood to be 

 the true labyrinthus. I am altogether disposed to retain the older 

 name, as there is no question about what shell Deshayes called laby- 

 rinthus. Dohrn is in error in saying that the mouth-parts and supra- 

 peripheral gutter are always most strongly developed in the smallest 

 specimens ; in the series before me these characters are most obvious 

 on several of the largest. Figures 87, 88, 89 of plate 39 are drawn 

 from one of these shells. The other forms included in the 

 synonymy are as follows : 



H. erecta Mousson (PL 40, figs. 100, 101, 102) is a small form 

 from Bogota, with the outer basal tooth more entering than in typical 

 labyrinthus ; the shell is thicker ; the color darker ; striation stronger, 

 the parietal lamella higher and the basal sinus more developed. 



Alt. 13, diam. maj. 30, min. 25 mill. 



H. annulifera Pfr. (= sipunculata Fbs.) (pi. 42, figs. 32, 33) is 

 smaller than the typical labyrinthus, and white around the periphery. 

 Alt. 13, diam. maj. 34, min. 29 mill. It is from Panama. 



A specimen of medium size (alt. 26, diam. 43 mill.) with the 

 peristome less complicated than in the typical form, and the supra- 

 peripheral gutter short and shallow is figured on pi. 64, figs. 14-16. 



