848 



SYSTEMATIC HISTOEY OF THE INFUSOEIA. 



species from Biddulphia merely on account of the absence of costae, without 

 violating natural affinity, and dividing Isthmia also. In Biddulphia, Klitzing 

 forms his species solely from the number of lateral costse and consequent 

 divisions (chambers) ; his species, however, have been generally rejected ; and 

 we think that, like similar characters in Actinoptychus and other genera, such 

 distinctions are essentially erroneous. 



* Valves with undulating margins and 

 tratisverse cost(S or depressions, 



Biddulphia pidchella (Gray). — Fms- 

 tiiles distinctly reticulated ; valves with 

 obtuse processes, and from one to five 

 smaller intermediate projections sepa- 

 rated by costee extending to the sutm^e. 

 SD. ii. p. 48, f 321. B. trilocidaris, Kutz. 

 (with two costae) ; B. quinquelocidaris, 

 Kiitz. (with four costae) ; B. sejjtemlocu- 

 laris, Kiitz. (with five costae) ; Denticella 

 Biddulphia, E. (central projection armed 

 with spines) ; B. australis, Montague ; 

 B. elongata, Montague ("udth broad cen- 

 tral portion), (ii. 46 to 50.) The di- 

 stinctive character of this species is the 

 costae or imperfect septa which separate 

 the projections. Lateral valves oval, with 

 undulated margins and a large pseudo- 

 opening at each end. In the young state 

 there is only one rib, and no interme- 

 diate projection. 



B. Regina (Sm.). — Valves with three 

 median elevations, the central one 

 largest, imarmed ; processes little ex- 

 ceeding the median elevation in length, 

 papillate, rounded ; cellules of elevation 

 distinct, those of valves and central zone 

 minute. SD. ii. p. 50, pi. 46. f 323 ; 

 Ro TMS. vii. p. 8. Dredged ofi" the 

 Island of Skye. Professor Bailey refers 

 this species to B. tridentata, and Pro- 

 fessor AVilliamson, according to Pro- 

 fessor Smith, to B. Tuomeyi. We have 

 seen no specimen, but trust to the well- 

 knoT\Ti accuracy of Professor Smith's 

 figures for its distinctness in the form 

 and comparative shortness of its pro- 

 cesses. 



B. tridentata (E.). — Lateral valves 

 dotted, having elongated, obtuse pro- 

 cesses, and one to three imequal inter- 

 mediate projections ; constrictions ap- 

 proaching the suture. EM. pi. 19. f 21. 

 = Denticella tridentata, E. (central pro- 

 tuberance armed) ; Denticella Tridens, E. 

 Fossil. America. Professor Bailey re- 

 fers B. Regina, Sm., to this species, but, 

 judging from the descriptions and figures, 

 they seem to us distinct. In this species 

 the processes are more slender, longer 

 than the intermediate projections, and 

 mostly constricted beneath the apex. 



Mr. Roper unites this species to B. 

 Tuomeyi, and is probably right in so 

 doing. 



B. obtusa(K.). — Frustulesvery smooth, 

 short, with turgid, obtuse, short horns, 

 and a very short intermediate process. = 

 OdojiteUa ohtusa, KA. p. 136. Heligo- 

 land, (xm. 30 to 32 a.) 



B. suhcequa (K.). — Frustules oblong, 

 very smooth; horns minute, without inter- 

 mediate projections. = Odontella suhcequa, 

 KB. pi. 18. 8. f 4, 5. Heligoland. Pro- 

 fessor Smith is probably right in regard- 

 ing the last two as states of B. aurita. 



B. Iceris (E.).— Has the habit of B. 

 aurita, but its valves are smooth and 

 tridenta,te. = Denticella Icevis, EM. pi. 33. 

 15. f 6. Antarctic Sea. Diam. 432". 

 Ehrenberg's figm-e of this species but 

 slightly resembles B. aurita: the horn- 

 like processes are elongated, slender, and 

 awl-shaped, and not the least inflated at 

 the base ; the intermediate margin also 

 is convex, and not elevated into a central 

 projection. 



B. Tuomeyi (B.). — Valves having ob- 

 tuse horns w4th swollen bases, between 

 which are from one to three shorter, 

 roimded projections, the middle one 

 largest, and often bearing two spines. = 

 Zygoceros Tuomeiji, BAJ. xhd. pi. 3. 

 f 3 to 9. Fossil. America, Patos guano, 

 (vi. 10.) The central zone is narrow- 

 linear, and slightly projects at each end ; 

 lateral valve^covered with shagreen-like 

 asperities, which are most evident on the 

 projections; processes generally con- 

 stricted. At the base of each swelling 

 is a short, linear, hyaline line which re- 

 sembles a perforation, but which we be- 

 lieve is really a smooth elevation. 



B. polymer a (E.). — Lateral valves 

 granidated, verj- broad and short ; angles 

 elongated into conical processes ; inter- 

 mediate projections several (about nine), 

 rounded, the central one largest. = Denti- 

 cella? polymera, E., BAJ. xhdii. pi. 4. 

 f 20 ; bdontella ? polymera, K. ; B. 

 Tuomeyi, Ro TMS. vii. p. 8. Fossil. 

 Bermuda. The lateral valves are so 

 short that the constrictions between the 

 lobes reach nearly to the base. This 

 species is remarkable for the great num- 

 ber of intermediate projections, of which 



