xv, 6 Shaiu: Campbellosphaera 497 



Close to the posterior pole of the specimen are two half -grown 

 specimens of an endophytic alga, of which one shows plainly 

 in the photograph (Plate I, fig. 1). More mature specimens 

 of Campbellosphaera on the same slide bear an abundance of 

 these endophytes in many stages of development. 



OBSERVATIONS ON LIVING SPECIMENS 



The earliest record in my notes pertaining to this genus 

 relate to observations on living material collected at Pasig on 

 July 30, 1914. Being mixed with larger species it was desig- 

 nated in the notes as "the smaller, spheroidal species of Volvox." 

 The notes under the above date are as follow: 



Collections of this morning show the smaller species with asexual re- 

 production. Very large gonidia radially vacuolate. Nearly closed daughter 

 spheres with four and eight large cells, probably gonidia, which appear 

 to be [derived from] undivided marginal cells of the saucer or cup stage. 

 [These] migrated inward and became distributed in the * * * sphere. 

 No protoplasmic connections in mother sphere. Cells of daughter very 

 elongate and compactly arranged. External wall of cells of mother sphere 

 very strongly convex on the outer side. Cells of the anterior pole larger 

 and farther apart and with much larger stigmata. 



Measurements of three living specimens were recorded under 

 the same date: 



Specimen 1. — Coenobium, 430 m wide by 480 ,u long. Somatic cells, sphe- 

 roidal, 7 m in anterior, middle, and posterior parts of coenobium. Inter- 

 cellular distances, 8 to 12 m, mostly about 10 v-. Cells in an area 180 

 fj- square, 180. Estimated number of cells in coenobium, 3,470. Gonidia 

 spheroidal; 82 by 85 *, 80 by 81 m, 86 by 88 m, 88 by 90 m, 89 by 94 m. 

 Daughters, 2; (1) 77 by 100 m, with four gonidia about 25 /", forming a 

 close group in one end; space about the daughter 90 by 106 m; (2) 77 by 

 100 m, with four gonidia about 25 m each also forming a close group in 

 the blunt end; space about the daughter, 115 by 130 m. Daughters rotating 

 on polar axis. 



Specimen 2. — 410 by 460 M. Cells, about 7 m (in equatorial region 

 somewhat less). Intercellular distances, about 8 to 10 m. Counted twenty- 

 six cells in an area 75 m square. Estimate of number of somatic cells, 

 2,635. Gonidia measured 42 m, 52 P, 64 *, 64 M, 64 * 72 m, 57 by 74 /<■ 

 (about to divide). Daughter, 80 p- collapsed, with eight gonidia about 18 

 ft in diameter. 



Specimen 3. — 410 by 480 n. Cells, about 7 m. Intercellular space, 8 

 to 10 m. Cells counted in 75 by 75 M space, 24. Estimate of somatic cells, 

 2,520. Gonidia; anterior circle, 50 by 60 M, 54 by 60 p, 46 by 48 m, 54 

 by 56 m; posterior circle, 72 M, 72 p, 62 by 70 m, 58 by 66 m. 



A record of the movement of the gonidia from the close cluster 

 in the back of the newly closed embryo to a more scattered dis- 

 tribution in the daughter coenobium was made on the same day. 

 In two embryos, at about 11.30 in the morning, the gonidia were 



