288 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



Frontal pores rounded, mediam sized, spaced fairly well apart. 

 Trisectional peristomial collar sometimes flares out excessively. 

 Peristome with fair-sized sinus in which is set a broadly oval avicu- 

 larium. Avicularia set at an angle against the frontal, with broader 

 end proximal. Lyrula medium sized. Tall ledges (cardelles) extend 

 high, halfway up the primary orifice sides, separated from the lyrula 

 by a sinus. Ovicells, opercula and mandibles unknown. 



Smittina alticollarita is named for its excessive, elevated, flaring 

 collar or peristome, from the Latin "altus" (high) and "collaris" 

 (collar) . 



Measurements: Minimum to maximum and average measure- 

 ments, in millimeters, are given below (for explanation see p. 721). 



Z-L, 0.864-0.936 (0.889) Pr-Or-W, 0.173-0.187 (0.176) 



Z-W, 0.504-0.619 (0.573) Se-Or-L, 0.158-0.216 (0.177) 



Av-L, (0.072, four readings) S^Oi-W, 0.158-0.202 (0.174) 



Av-W, 0.058-0.065 (0.061) Ly-L, 0.029-0.036 (0.030) 



Pr-Oi-L, 0.122-0.130 (0.128) Ly-W, 0.058-0.072 (0.061) 



Zoarium: The white, smooth-textured, fine-patterned holotype i 

 colony is 9 mm. by 10 mm, and consists of about 100 hexagonal 

 zooecia which are large enough to see with the unaided eye and which 

 form a thick-walled heavy crust on the substratum. The zoarium is 

 without mandibles, ovicells, or soft polypide remains. 



Zooecia: The zooecial frontal is a gently convex tremocyst, more 

 often roughly granular than beaded, although both textures may 

 occur on the same zoid. The frontal pores are rounded, of uniform 

 size, fairly well spaced from each other, the peripheral pores being no 

 larger than the more central ones. The mural rims are thin salient 

 threads. The most elevated part of the frontal is the peristome. 



Avicularia: Present in some zooecia and absent from others. 

 Although few are present they appear to be of uniform size and in the 

 same location. They are placed neither vertically nor horizontally 

 but at an angle to the frontal, in the gap formed by the two approach- 

 ing ends of the peristomial collar. Their proximally directed beak is 

 longer than the membranous avicularial back area. The mandible, 

 judging from the shape of the beak, should be thumb-nail shaped. 



Orifice: The orifice is frontal. Its distal wall is formed with the 

 aid of the next distal zoid. The peristome is raised distally, in the 

 young zoids like a head shawl (pi. 24, C), It shows considerable 

 variation in the same colony (holotype) — from the simple thin collar 

 through various intermediate stages (pi. 24,A,D,F) to a 3-lobed 

 moderately thickened elevated collar (pi, 24,B), There is even a 

 higher peristome on an old, 2-zoid paratype (pi. 24,E), 



The secondary orifice is pear shaped, the sinus being the narrower 

 part. The medium-wide proximal sinus is really an interruption in 

 the peristome where the avicularium, if present, is placed. 



lU 



