PALEOZOIC TIME — LOWER SILURIAN. 503 



of Seely (1885), who referred it to the Sponges, and Siphonema of Bornemann (1886), 

 who placed it among the Algae. It is made a calcareous Alga by Rothpletz (1891). 



2. Spongiozoans. — ^osporeg'ia {Astylospongia) BoRmeri B. and E. varians B. occur 

 at the Miugan Islands. 



3. Actinozoans. — Columnaria incerta B. and C. parva B. ; the Cyathophylloid, 

 Streptelasma expansu7n H. j Monticidipora patula B., 31. adhcerens B., from Canada. 



i. Echinodenns. — (1) Crinoids. — Palceocrimis striatus (Fig. 627), the body, show- 

 ing the five radiating ambulacral grooves at top ; Blastoidocrinus carcharidens B. 

 (2) Cystoids. — Malocystites Murchisoni B. (Fig. 628) has the body nearly spherical 

 (whence the name, from the Latin malum, an apple), the ambulacral grooves irregularly 

 radiating; M. Barrandi B., PalceocystUes tenuiradiatus B., which is common, and has 

 been identified but doubtfully, from crinoid stems from crystalline limestone of West Rut- 

 land {Am. Jour. Sc, III. iv. 133) ; also P. Dawsoni B., P. pulcher B., P. Chapmani'B., 

 from Canada. 



5. Molluscoids. — Other species are Bafinesquina incrassata H., which continues into 

 the Trenton Strophomena (?) pUcifera H., Bhynchonella acutirostris H., B. altilis H., 

 Bafinesquina fasciata H., in the Upper Chazy ; Lingula Lye.lli B., L. Huronensis B., etc. ; 

 Orthis imperator B., a species nearly li inches across. 



Note. — Hall proposes (1892) the generic name Bafinesquina for the species of Stro- 

 phomena of the type of S. alternata, restricting the name Strophomena to resupinate species 

 like S. planumhona. He applies the name Leptcena to forms like S. rhomhoidalis, and 

 restores Pander's generic name Plectambonites to species commonly known as Leptcena, 

 as L. sericea and L. transversalis (Hall, Pal. JY. Y., vol. viii.. Genera of Paleozoic Brachi- 

 opoda, 1892). 



6. Mollusks. — (a) Lamellibranchs. — Cypricardites (Vanuxemia) Montrealensis B. 

 — a species nearly 1 .} inches long. 



(6) Gastropods. — Besides the species figured, other common kinds are Baphistoma 

 planistrium H., Pleiirotomaria biangulata H., P. antiquata H., Bucania sulcata {Bucania 

 differs from Bellerophon only in having the outlines of the spire show externally on 

 either side). 3Ietoptoma dubia H., Platyceras auriformis H. 



(c) Cephalopods. — Orthoceras rectiannulatum H., also found in the Birdseye lime- 

 stone ; 0. temdseptiim H., septa very thin and rather crowded ; 0. velox B., Montreal, 

 Mingan Islands; 0. diffidens B., Mingan Islands; 0. AHumettense B. (which is also a 

 Black River limestone species) . 



7. Crustaceans. — The Trilobites, Illoinus Arcturus H. ; Asaphus obtrisus H., A. (Iso- 

 telus) canalis Conr., Xew York and Canada, A. marginalis H., and also Quebec group 

 of Newfoundland. Bathyurus Angelini B.; Ceraurus Satyrus B., at Montreal. The 

 earlier genera, Dicellocephalus, Crepicephalus, Menocephalus, Bathyurellus, Loganellus, 

 NiJeus, are not represented, so far as known, in the Chazy or later periods. 



The Ostracoids, Leperditia Canadensis Jones, Fig. 638, from Grenville, Huntley, and 

 elsewhere in Canada ; L. amygdalina Jones, from near L'Original, Canada. 



In the gorge of the Kentucky River, near the mouth of Cooper's branch, Ulrich reports 

 a limestone stratum (150' thick) as affording the Chazy species Maclurea magna, Baph- 

 istoma. pUinistrium, Bhynchonella dubia H. , Sulcopora fenestrata, Leperditia Canadensis, 

 with Orthis suboequata Conr. a Trenton species, Orthoceras explorator B. a Quebec species 

 and 0. furtivum B. a Calciferous species ; with also species of Bathyurus, Dalmanites, 

 Pterotheca, and the Trenton Bryozoan Mitoclema cinctosum Ulr. 



Other species described by Billings, in Can. Cf. Bep. of 1863, are MonticuUpora (Sten- 

 opora) fibrosa ; Bhynchonella orientalis, Camarella varians, C. longirostris, Orthis platys, 

 0. borealis, 0. Porcia, 0. acuminata, 0. disparilis Con. (from the Chazy and Trenton) ; 

 Pleiirotomaria calyx, P. docens ; Illcenns glohosus, I. Bayfieldi, Sphcerexochus parvus 

 (from the Chazy and Black River), Harpes antiquatus. 



