190 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



I. Celhtlaria Pallas, 1766, (restricted). Zocecia unilateral, in two alternating rows, 



mostly protected by lateral spines, either simple or dilated. Vibracula and lat- 

 eral and median avicularia present. Type C. scrnposa.* 



a. Subgenus Cclhilaria ( ^ Scrupocellaria, pars, Gray, Busk). Lateral spines all simple. 



b. Subgenus Cellarina Van Ben. (incl. Triccllaria Flem., 1828). One of the lateral 



spines usually more or less dilated and often expanded in a shield-like form iu 

 front of the zocecia. Two New England species : C. scabra Van Ben. and C. ternata 

 (Sol.), with varieties (/racilis and duplex (Smitt). 



The name Tricellaria (given to ternata) might have been adopted for this sub- 

 genus, but it is very inapplicable to the group, and even to the type-species, 

 as now known. 



II. ScnipariaOken (restricted) {^ ScrupoceUaria, pars, Gray; Cauda Busk, non Lamx.). 



Lateral avicularia and vibracula absent. A lateral spine develops into a jiro- 

 tective (often frondose) shield. Type S. reptans (Linn^), not yet found on the 

 American coast. 



III. Bugidopsis Verrill {^=CeUularia, pars, Busk, non Pallas). Characterized by the 



simple, unarmed zocecia, arranged in alternating rows, and destitute of avicu- 

 laria, 'sdbracula, and shields. Type C. Peachii (Busk), Gulf of Maiue and Bay 

 of Fundy. European seas, north to Sj)itzbergcn. 



As no species of the last group was originally iucluded in Cellularia, 

 it is inadmissible to restrict that name to it. Either reptans or seruposa 

 should be taken as the type of Cellularia, both having been originally 

 included' by Pallas, as well as by most subsequent authors. Scruparia t 

 Oken (1815) originally included not only the group that had x)reviously 

 been named Eucratea by Lainoiu'oux (1812), but also 8. reptans. There- 

 fore there seems to be no good reason why it should not be restricted, 

 as above, rather than be displaced by the much later and more objec- 

 tionable name, Scriqwcellaria. Menipea, used by Busk and others for 

 Cellarina, is inadmissible, in that sense, for the original group named 

 Menipea by Lamouroux is a valid and very distinct genus. Canda (Lamx., 

 181G), adopted by some for Cellularia reptans, cannot properly be so used, 

 for the original type is a distinct genus. 



Porelliiia stellata Verrill, Amer. Jour. Sci., xviii, p. 5o. 



A large species, forming radiating patches on shells, etc. Zocecia ar- 

 ranged in quincunx, large, broad, moderately convex, white, shining, 

 mostly imperforate and smooth, the marginal ones more or less perfo- 

 rate in front. Apertures nearly semicircular, the proximal edge straight 

 or nearly so, often with two spines on the distal border; median pore, a 

 short distance from the aperture, large, nearly circular, provided with 

 numerous, slender, convergent spinules, which nearly reach the center, 

 giving the pore a stellate appearance. Avicidaria near the lateral mar- 

 gin, about opposite the median pore, varying in size and form ; in the 

 same colony some are short triangular, others long triangular, while 

 others with a long and acute erect tip show the transition toward vibra- 



* This species has been recorded from the Gulf of St. Lawrence by Packard and 

 othe-s, but I have myself seen no American examples. 



tThis name has recei^tly been given to a new genus, in a new sense, by Hincks, in 

 accordance with a practice that is nearly always unsafe, as well as confusing. 



