844 



SYSTEMATIC HISTOKY OF THE INFUSOEIA. 



ment of its gi'aniiles, it is easil}^ known 

 by its inflations. Disc large, smoke- or 

 lead-coloured, with a narrow, distinct, 

 finely striated rim ; inflations remote 

 from the margin, and having a bright 

 point at the outer edge, placed at the 

 base of an elongated, clavate, not very 

 conspicuous process. 



2 * Disc not bullate heneath the processes. 



A. scaler (Ralfs, n. sp.). — Disc with 

 oblong submarginal processes, crowded 

 radiating series of minute granules, and 

 scattered raised points. Peruvian guano. 

 Processes 3 to 5, connected by indistinct 

 grooves with the very minute umbilicus. 

 In the front view this species resembles 

 a Cerataulus, its lateral portions being 

 turgid, and, in addition to the processes, 

 rough with minute apiculi; connecting 

 zone marked by faint longitudinal lines. 



A. Kittoni (Aruott, MS.). — Disc hya- 

 line, with 3 to 8 submarginal crescent- 

 looking processes, connected by radiant 

 rows of minute granules, with an umbi- 

 lical rosette of oblong cellules. Recent, 

 New Zealand and Monterey Bay ; fossil, 

 Monterey stone. An elegant species, 

 distinguished by its somewhat mammi- 

 form processes, which, being directed out- 

 wards, appear lunate. Granules pmicti- 

 form, proceeding from umbilicus to 

 processes in pencil-like rays ; intei-val 

 between the processes bisected by similar 

 pencils, but less conspicuous, and with- 

 out fuiTows ; the rest of the granules in 

 oblique lines, as in A. Petersii. ['ypT J^ 



A. Jb72«somV(Ai*nott,MS.). — Disc pale, 

 with a circular, perforation-like umbili- 

 cus, and crowded radiating series of gra- 

 nules becoming more numerous as they 

 proceed outwards, so as to appear forked ; 

 processes within the margin, roundish, 

 small. Algoa Bay guano. The rays, 

 near the margin, become more numerous, 

 with smaller granules, so as to look like 

 striae; sometimes the processes appear 

 within a faint circle. A. Johnsonii some- 

 what resembles A. Kittoni, but is less 

 hyaline, with more conspicuous gra- 

 nules, and processes more distant from 

 the margin. 



A. Criix (E.). — Disc with close, radi- 

 ating, forked series of large pearly gra- 

 nides, which are crowded at the centre, 

 leaving no blank space ; processes some- 

 what distant from the margin. = ^. Crux, 

 EB. 1844, p. 76; EM. t. 18. f. 47; Eu- 

 podisciis Crux, KA. p. 135. Fossil. Vir- 

 ginia. . We are indebted to Professor 

 Arnott for coiTecting the error we had 

 fallen into, of confounding it with A. 



Kittoni. In general appearance it agrees 

 with A. Co7nheri and A. margaritaceus ; 

 but the processes are more remote from 

 the margin, and the connecting furrows 

 obscure ; it difiers essentially from most 

 other species in having large granules 

 at the centre of its disc, instead of a 

 blank space ; margin striated. 



A. tnargaritaceus (Ralfs, n. sp.). — Disc 

 pale, with oblong submarginal processes, 

 an iiTegular, perforation-like umbilicus, 

 nmnerous, close, moniliform, radiating 

 series of large, pearl}- gTanules, and in- 

 conspicuous connecting fmTOws. Patos 

 or Californian guano. = A. Crux, EM. 

 pi. 35 A. 16. f. 2. Disc large, with from 



8 to 10 rather small processes ; umbilicus 

 usually iiTcgular, hyaline, looking as if 

 denuded of granules, sometimes very 

 minute and suiTOunded by a circlet of 

 larger granules. Two simple series of 

 equal granules lead to each process, be- 

 neath which, by a slight separation, they 

 leave a triangular hyaline space ; the 

 other series are dichotomously divided, 

 and near the margin their granules be- 

 come smaller, or even punctiform, and 

 resemble stride. 



A. Comber i{A.Ynott, MS.). — Disc lurid ; 

 gran ides large, irregularly scattered round 

 the iiTegidar perforation-like imibilicus, 

 the rest arranged in crowded, forked, 

 radiating lines; processes oblong, sub- 

 marginal, with conspicuous connecting 

 furrows. San Filipe guano. Processes 

 2 to 6. A. Comheri in character ap- 

 proaches closely to A. margaritaceus ; its 

 granules, however, are smaller and more 

 irreaidar near the umbilicus, and the 

 furrows leading from the processes are 

 much more conspicuous ; but the most 

 obvious distinction of this species is its 

 lurid appearance. 



A. Beeverice (Johnson, MS.). — Disc 

 smoke-colom-ed, with an irregular blank 

 umbilicus, rather distant radiating lines 

 of large pearly granules, striated mar- 

 gin, and (3 or 4) roundish submarginal 

 processes. New Zealand. Of this beau- 

 tiful species we have seen only one spe- 

 cimen. The disc is small, apparently 

 nearly flat, with very distinct granules, 



9 or iO in -001", on a dark ground; two 

 series leading to each process, wider 

 apart and more parallel than the rest. 

 (VI. 5.) 



A. Broiv7ieii (Noi-man, MS.). — Disc 

 coloured, vAth a minute umbilicus, close 

 radiating series of granules, and two or 

 three roundish intramarginal processes. 

 Shell-cleanings, California and else- 

 where in the Pacific. Fossil, Monterey 



