Navictdacea.'] iNFtrsoElAt animalctiles, 465 



GosrrnoNEMA apiculatutn. — Rhomboid and wcdgc-sliapcd ; dorsally, 

 extremities contracted, long; anterior cxti'emity acute (P. 15, figs. 

 28 and 53.) 



G. Cijgnus. — Narrowly linear-lanceolate, turgid at the middle; 

 anterior extremity obtuse, but long and linear. North America. 

 Kiitzing thinks this probably identical with SpJienella rostellata (Kiitz.) 

 G. Glaus. — Ovate- oblong, turgid; anteriorly rounded, and with a 

 slightly narrow neck. It has a general resemblance to G. clavatum, 

 but is shorter, stronger, and more obtuse. North America. 



G. laticeps. — Habit of G. coronatum but shorter, and with the 

 anterior end wider than the central pai't of the body, on the lateral 

 aspect. Iceland. 



G. nasutum. — Ovate laterally ; the attached or posterior end short 

 and slender ; no neck ; not constricted anteriorly, but furnished with 

 a small point (apiculate.) Approaches G. Augur, but is shorter and 

 stronger. New York, 



G. (?) Pupula. — Linear-clavate laterally ; margin undulate ; striae 

 few, and appearing like so many constrictions ; apex often narrower 

 than the rest of the body. Possibly a Meridon. North America 

 and Iceland. 



G. subtile. — Slender, dorsum with two constrictions ; anterior 

 extremity small, obtuse, sub-truncate at the extremity of a long and 

 slender neck. 



G. Turris. — Larger and longer ; anterior extremity elongated, 

 equalling the body in breadth ; its apex suddenly attenuate and 

 wedge-shaped. Approaches G. gracile, but is thicker. North America. 

 G. Vibrio. — Linear-lanceolate, elongate ; gradually tapering to 

 the anterior extremity or head, which is subacute and prolonged so 

 as to be sub-rostrate. This species is more slender than G. gracilis, 

 and approaches Pinnularia Amphioxys. Cayenne. 



G. Herculeanum. — Very large, minutely stiiated ; dorsally clavate, 

 with the middle dilated, the ends attenuate and rounded ; becomes 

 slenderer near the pedicle. Pedicles (foot-stalks) long, hyaline, 

 dichotomous. Length of testules 1-2 16th; of the compound arbo- 

 rescent being ( — arbuscle) l-12th to l-6th. Found in Lake Micliigau, 

 at Niagara, and in Oregon. 



G. splicer o2)honm. —~ Small, delicately striate ; clavate dorsally ; 



