110 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



Additional material: D. 3849a, on worm tubes attached to 

 intertidal rocks, Acapulco, Guerrero, Feb.; D. 1869, near Guaymas, 

 Sonora, May; D. 7109, Punta Aguja, Bahia Concepcion, Baja Calif., 

 Mar. 



Gruoriella hancockii sp. nov. 

 Plate 11, fig. 9; Plate 33, fig. 1 



Thallo magnopere calcificato, 3-6 cm. lato, 400-1000 ju, crasso, super- 

 ficie plus minusve levi, haud striata, rhizoidibus unicellularibus, per 

 aetatem prominenter stratificato ; tetrasporangiis in nematheciis 65-75 /u. 

 crassis, 70-110 fi sub superficie mersis; paraphysibus intercalaribus ap- 

 parentibus in seriebus cellularum perithalli, 6-7 cellularum elongatarum ; 

 tetrasporangiis (haud maturis) 70-85 /x longis, 11-20 /* latis. 



Thallus crustose, heavily calcified, especially in the lower two-thirds, 

 firmly adherent to the rocky substrate, dull brownish or purplish red to 

 chalky pink when dry, forming crusts 3-6 cm. broad or completely cover- 

 ing small rocks, 400-1000 /x thick, the surface moderately smooth, with- 

 out striations ; young thallus margins showing numerous short, unicellu- 

 lar rhizoids and the characteristic Cruoriella hypothallus of converging 

 and diverging fan-shaped groups of cells; old thallus parts prominently 

 stratified, apparently by successive periods of growth; perithallus cell 

 rows more or less vertical, to 34 ju, in diameter below, 7-9 ix. in diameter 

 above, the upper several tiers usually uncalcified; tetrasporangial nema- 

 thecia immersed in the stratified thallus 70-100 /* below the surface, 65- 

 75 II thick ; paraphyses appearing to be intercalcary in the perithallus cell 

 rows, of 6-7 elongated cells; tetrasporangia more or less fusiform, 70- 

 85 ju, long, 11-20 [I wide at time of the first division; mature sporangia 

 not observed ; sexual reproduction not observed. 



Type: Holotype is Dawson 9050, April 27, 1950, in box 56282, 

 including slides 1895-1899, in HAHF. 



Type locality: South shore, East Island, Islas San Benito, Baja 

 California, Mexico. 



Additional material: D. 9186, Bahia Asuncion, Baja California, 

 Apr.; D. 6830, Cabeza Ballena, Baja California, Mar. 



Although the tetrasporangial nemathecia are immature in the type, 

 the second division not having been completed, the immersed condition is 

 unique and marks this species as a distinctive one of this genus. 



